Time for a new Open Thread on the Fukushima Daiichi nuclear crisis. Please use this post to put any new comments about the situation (including technical information, situation updates, analysis, questions, reflections, etc.). Note that the Open Threads on BraveNewClimate.com are a general discussion forum; please follow the commenting rules, although the ‘stay on topic’ rule obviously does not apply as strictly here.

Analyses suggest most of the fuel in unit 1 is now the bottom of the reactor vessel (Image: Tepco)

For context, below is a brief list of recent events since the previous FD post. (For day-by-day detailed updates, I suggest you follow the ANS Nuclear Cafe news and updates (includes links to official reports like JAIF and TEPCO and news feeds from NHK, NY Times, etc.), see also NEI updates, and other links provided in previous posts.)

1) Fuel melt: Recent analysis suggests that the fuel assemblies in unit 1 were almost completely melted in the days following the March 11 earthquake and tsunami. The ‘corium’ (melted actinide fuel, contained fission products, clad etc.) then dropped to the bottom of the reactor pressure vessel (RPV). It is now suspected that during the initial accident, the fuel rods of Reactor No. 1 could have been fully exposed for up to 17 hours, and the earthquake may have caused some structural damage that led to pipe leakage and other problems, in addition to the severe troubles caused by the extended station blackout following the tsunami (which remains the principal cause of the problems).

The temperature of the RPV is now in the range of 100℃ – 120℃, and so the core (or what remains of it) and RPV are stably cooled. That is, this new information is part of a post mortem analysis of events and timeline of the accident, rather than a trigger for a new urgent crisis.

Despite this, this announcement inevitably led to a whole new wave of speculation (and hype), including rumours alleging “1) “melt down in unit 1 has burned a hole through the bottom of the containment vessel” and 2) “that there was a detonation of the fuel rods & pieces of fuel rods were found two miles from the reactors”.

What is the reality? A close nuclear engineer friend of mine says the following:

There is no evidence that the molten fuel has melted through the bottom of the reactor pressure vessel. The latest TEPCO analyses suggest the molten fuel is submerged in water at the bottom of the pressure vessel. Some TEPCO reports mention about “holes” in the containment vessel. What they mean by “holes” is that the seals on pipe penetrations, etc. may not be leak-tight, and hence steam and/or water leaks out of the vessel.

The second claim is absolutely not true. The site is highly contaminated. The radiation mapping of the site, which has taken more than a dozen surveys (because you can do just a few at a time) indicates the contamination is concentrated in the rubble. The steam vented to the reactor building would have carried along volatilized I and Cs, some of which were condensed onto the walls and surfaces, which then blew up in hydrogen explosion.

The soil sample around the site indicated detection of minute quantities of plutonium (some samples included both Pu-238 and Pu-239, and others just Pu-239). The magnitude was within normal fallout contamination ranges. It is not clear whether these Pu detections indicate they are old contaminations or fresh from Fukushima Daiichi.

Work has already started on constructing a cover over the damaged reactor building of unit 1 to prevent the spread of radioactive materials. Similar covers for the reactor buildings of units 3 and 4 are now being designed. Unit 2 will not require a cover as the reactor building remains intact.

3) New theory for Unit 4 hydrogen explosion: An apparent contradiction at the unit 4 spent fuel pond was the lack of visual damage of the fuel assessmblies and the difficulty in explaining how radiolysis alone could have evolved so much hydrogen — especially if the fuel was never exposed to air. There is now a new explanation for the source of the fire. TEPCO stated:

The SGTS line of Unit 4 merges into Unit 3 exhaust pipe and it might be a case where hydrogen gas came from Unit 3 flew into Unit 4 reactor building. But this estimation remains presumptive and we have not reached to conclude that the vent operation at Unit 3 caused the explosion at Unit 4. And it is not clear the open/close status of valves in SGTS and when and what amount of hydrogen was generated/ flew in the Unit 4 as of this moment.

Some further details here. This is also a plausible explanation of why the unit 4 storage pool had a low level of radioactivity, and why the two fires extinguished themselves without intervention.

4) Worker death: A sub-contractor at the site has died — he had been working on the drainage system of the centralised radioactive waste store. Tests showed that the worker had not been contaminated with radiation (he was exposed to 0.17 mSv), and he appears to have unfortunately died of a heart attack (he was in his 60s). To underscore: sad as this is, ut is not a radiation-sickness-induced death.

But what if Japan decided to retreat from their plans to expand nuclear power to meet 50% of their energy needs by 2030? What would it cost them, in terms of (a) increased emissions of greenhouse gases, and (2) financial alternatives. In a superb analysis, The Breakthrough Institute looked at the possible alternative scenarios in their piece: The Costs of Canceling Japan’s Plans for Nuclear Power.

The bottom line is this: (i) if coal and/or gas is used, emissions will rise 15 to 26% and the cost will be $90 — 150 billion in capital costs and a $17 — 27 billion annual hit in terms of increased imported fuel (coal or LNG); (ii) if attempted with renewables, the cost would range from $330 billion (wind, no storage) to $690 billion (solar, with some generous assumptions, representing a 190-fold increase in installed capacity). I’m reminded of what George Monbiot said recently, “The Lost World“:

The case against abandoning nuclear power, for example, is a simple one: it will be replaced either by fossil fuels or by renewables which would otherwise have replaced fossil fuels. In either circumstance, greenhouse gases, other forms of destruction and human deaths and injuries all rise.

Which do you want, folks? If you care about climate change mitigation and clean, reliable and cost-effective power, then it’s time to get real about nuclear energy.

Not as long as fossil fuel industry continues using their right to employ money-amplified free speech to persuade the world that man cannot possibly change the world’s climate and that continued use of their products is mankind’s wisest course of action.

As well drummed-up concerns about nuclear safety because of exaggerated news accounts of the damage inflicted by the Three Mile Island/Chernobyl accidents, along with the dramaturgy wrought by Hollywood, have allowed fear mongering to prevail over sound science.

Increasingly, it seems the choice is between fossil fuels and nuclear. Your point is a very good one, Barry, that every MW of renewables used to replace nuclear is a MW of fossil that keeps on burning.

Given the paranoia existing in the general populace about nuclear, and the difficulty in educating same about the very real threat posed by global warming (thanks in no small part to the efforts of the fossil fuel industry), I come to the following conclusion:

The possibility of H2 backflowing from R3 into R4 bdlg was discussed in a March 20th thread (see below). I thought it was unlikely at the time.

The only way (that I can think of) that R3 vent vapors to a common stack could backflow into R4 is if the common line at the R3/R4 junction to the stack was blocked. (See sketch in article) Only if this is the case, could pressure build to backflow into R4. Otherwise, the path of least resistance is up the stack. The common line could be examined to see if it is blocked.

March 20 comments
“As far as R3 vent vapors going to common vent stack and then backflowing to R4 and ending up in the building top, I think that is unlikely. High stacks have chimney draft effect which sucks on both R3 and R4 if common connection”

“@David B Benson 12:42: Isn’t H2 generated from R4 SFP low water and hot fuel assemblies a potential source? Is it probable?, well we at least know that it didn’t come from R4 reactor vessel or primary containment since that had no fuel assemblies. The H2 backflow from R3 (damaged at the time) to R4 via common vent stack seems to me to be unlikely

There is no evidence that the molten fuel has melted through the bottom of the reactor pressure vessel. The latest TEPCO analyses suggest the molten fuel is submerged in water at the bottom of the pressure vessel. Some TEPCO reports mention about “holes” in the containment vessel. What they mean by “holes” is that the seals on pipe penetrations, etc. may not be leak-tight, and hence steam and/or water leaks out of the vessel.

Actually, they mean precisely that there are holes in the reactor pressure vessel, created by molten corium.

One of the reactors at Japan’s crippled Fukushima nuclear power plant has a hole in its main vessel following a meltdown of fuel rods, leading to a leakage of radioactive water, its operator said on Thursday.

[…] “There must be a large leak,” Junichi Matsumoto, a general manager at the utility told a news conference.

“The fuel pellets likely melted and fell, and in the process may have damaged…the pressure vessel itself and created a hole,” he added.

In the WSJ article, manager Matsumoto estimates ~10% of the corium has collapsed into the primary containment vessel, with the remaining 90% still being in the RPV. They say they don’t think the corium has escaped the primary containment, although it does have holes and has leaked thousands of tons of contaminated water. (According to the graphic, the theory is that it is the torus that has failed).

I’m not so sure that the majority of Australians are against nuclear power.I suspect that the majority of Australians have not thought very much about climate change let alone nuclear power.

How to pay off the mortgage on the McBox in the McBurb without doing without too much else is probably uppermost in their “minds”.Throw in the AFL/ARL scene or some other drug of choice and we have something
close enough to anasthesia.

This is one of the main reasons why we have such (perjorative deleted)incompetents running the country and a set of equal incompetents in waiting for when it is their turn.

I have no idea how this fog of unconsciousness can or will be penetrated,except,perhaps,by a collapse of the system.

@uvdiv: Thanks, as I noted in the post, I was reproducing there what my nuclear engineer friend had said — he may or may not be correct, just as Matsumoto may or may not be correct (there are always “may”s in these speculations). The reality, as I know you appreciate, is that none of this can be confirmed or denied in the near future. The leakage of water from either holes or leaks/cracks, is obviously indisputable.

I was interested in your “political edict” statement regarding the Hamaoka Nuke Plant. At first I thought it was the usual brush it aside statement and then I thought that maybe you have a point.

Looking up geological and historical information I find that the power station is on land that would possibly be affected by liquefaction in the event of a major earthquake. It also lies on top of the Tokai fault. The historical records show that every 100 to 150 years there is a massive earthquake known as the Tokai, with Tsunami. The evidence suggests it is now due. Japan has been supposedly preparing for this since the 70s. In hindsight this powers station looks very vulnerable and with a reasonable chance of an incident soon, this station is the obvious one to pick on. In my opinion the political angle is to try and protect the overall industry by being seen to take action. I think the government needed to show that they are taking a stand and picked on the obvious candidate which has been a focal point for anti-nukes. The fact is that nuclear power stations in the area and in places like Taiwan, West Coast of US are, if you take a rational approach with historical data, potentially are in some danger. My opinion from this is that politics and commerce are the reason why the logical conclusions from historical data and now recent events is suppressed.

One thing I would like to know from the technical guys is what happens to a power station on cold shutdown if it is hit by a major event? Is it completely safe or could you get meltdown if cooling systems stop?

BarryBut what if Japan decided to retreat from their plans to expand nuclear power to meet 50% of their energy needs by 2030? What would it cost them, in terms of (a) increased emissions of greenhouse gases, and (2) financial alternatives.
Its probably important to distinguish between putting on hold plans to expand nuclear as distinct from either closing down existing nuclear or maintaining existing reactors ( and replacing aging gen II with genIII). I don’t think Japanese Gov is planning to abandon nuclear just not expand further. Most genII reactors will have to be replaced soon in any case.
It is probable that any new reactor not built in Japan is another reactor available to be installed in another country.

assumptions of Breakthrough Institute
(1) capacity factor of existing nuclear will increase from 72% to 90%(ie similar to US).
(2) renewable alternative using wind assumes wind capacity factor of 20%, BUT DOES NOT assume this increasing to >30% the value of new wind turbines operating in US and Australia..

The interim findings of the UK inquiry into the implications of the Fukushima accident for current and future nuclear power in the UK have been released. The principle finding:

Conclusion 1: In considering the direct causes of the Fukushima accident we see no reason for curtailing the operation of nuclear power plants or other nuclear facilities in the UK. Once further work is completed any proposed improvements will be considered and implemented on a case by case basis, in line with our normal regulatory approach.

Barry, I would like to see some informed comment on the results of the recent airborne surveys and Cs137 deposition maps for Fukushima region. I think these are important because they represent the real impact going forward. Although I am pro nuclear, I am somewhat concerned by what to me are higher than expected levels of contamination. This will not be a good advertisement for industry. What is the way forward for this area based on Chernobyl experience and what can be done to help clean up?MODERATOR
It is expected on BNC that links/refs be provided to assist in interpretation of data etc. Could you please supply these for your comment on the “recent airborne surveys….”.
Please ensure future comments follow this BNC commenting policy or your post may be deleted and you will be asked to re-submit including refs.

I am disturbed by the uniting of the accidents at Chernobyl and 3 Mile Island. There were NO releases of radiation from 3 mile. The film on the area fences was not fogged. An anomaly occurred 20 years later ; there were fewer cases of cancer in the surrounding area than in the previous 20 years.
There was a planned release. to the atmosphere which was to regulate pressure in the containment.
The main result was the economic loss of one of the two plants and the scare that the media caused among the people.
Some engineers question the need for the controlled meltdown insisting that the plant was trying to shut down, but NRC was overcautious.

With regard to Rick’s comment above, there are aerial maps of contaminationhere. The dose going forward from today is negligible according to most of these, for most areas, although that is sometimes hard to discern as the integrated dose starting mid March is used eg. in 18 April slideshow.

The Chernobyl experience is that areas with Cs-137 deposition above 40 Ci/km^2 (1.48 MBq/m2</sup) are permanent exclusion zones, and will remain so for centuries. This is the red and most of the yellow region in the deposition map — on the order of 1,000 km^2. (Assuming Japan uses the same radiation protection standards as the 1980s USSR).

But right now you have slightly over twice as much external dose from Cs-134 than from Cs-137. (Cs-137/Cs-134 activity ratio is about 1.2, and Cs-134 has about 2.7 times more gamma energy per decay than Cs-137). So the dose rates are about three times higher than just the Cs-137 component.

I’m not at all sure what’s going to happen with this fallout contamination. At the very least, several 100 km^2 (around 100,000-200,000 population) will be an exclusion zone. At a more conservative level, for a 10 mSv/year external dose standard (outdoors), you’d evacuate over a million people, until Cs-134 decays. But then that ignores shielding of building walls; indoors dose rates are significantly lower than outdoors.

Actually there were small radiation releases from Three Mile Island (venting the containment building, mostly noble gases), though of course the doses involved were far smaller than from Fukushima. An average of 0.01 mSv to the two million people in the area, and no higher than 1 mSv (at the site boundary).

> no evidence that the molten fuel has melted
> through the bottom of the reactor pressure vessel

Barry, would you ask your friend what (if anything) _could_ be looked for as evidence either way, on this question?

For example, would melted pressure vessel alloy, or overheated/burning concrete, add detectable trace material into the escaping water or steam, distinct from the material otherwise being vented?

Searching site:nrc.gov turns up many references to
“ex-vessel phenomena (e.g., core concrete interactions)” — but it’s a vast amount of material over 40 years. Your friend might know if this question is answerable, and if so, what they’d be looking for now.

As for Japan replacing their energy production, I would imagine they did a risk analysis and figured it could be cheaper in the long run to go for renewables, its a shame that the technology is not cheap enough to compete with coal and NG, but neither was nuclear, Japan made a concious decision to remain independent from FF because they lack FF, renewables are still Japanese and hopefully they can surpass Germany in terms of green energy, heck they have much much better solar potential just because of seasonal variability

@Len…it’s not true there was “no release”. There were several releases on purpose with a ‘plume’ of the release traveling southwest to northeast from the plant. They did not appear to cause any health risks albeit anti-nukes dispute this.

“Richard T. Lahey, former chair of nuclear engineering at Rensselaer Polytechnic Institute, in Troy, N.Y., was quoted ….:
… Lahey elaborated on his analysis for IEEE Spectrum ….
… based on the data sources seen by him and colleagues .…
… his best take is that “all cores have melted, and it appears as though Unit 2 has melted through.”

His conclusion about reactor No. 2 comes largely from the amount of radiation in the water found there and the chemical contents of that water….
… where the fuel escapes through the bottom of the chamber, the … molten goop from the reactor—will vaporize the concrete and create dangerous radioactive aerosols. “The water will scrub out the radioactive aerosols” ….

——–
IEEE said they would have followups on this. I did not find them when I searched for them.

No reactor on the West Coast of the US made the ‘Top 10’. Diablo Canyon in California came in at #15 with a 1/23,000 year chance of seismic damage which is somewhat lower then Indian Point in New York with a 1/10,000 year risk.

Until we privatise the emissions of polution via a cap and trade system individuals will continue to utilise fossil fuels at the expense of everyone else. Once people have to pay, then Nuclear will get a big boost in Australia.

Hopefully before then the government doesn’t waste too much money on feel good policy. It’s simple common sense that the impacts from nuclear are wildly over stated but whilst there is no actual cap on emissions, Enviro-religious types will continue to parade around telling us we have sinned and putting subsidised solar panels on their houses, at our expense, and milking guilt money from the public.

Is it possible that it would be better to stop trying to cool the cores with water in the current circumstances? Can the core material still generate enough heat to cause structural damage? If the core just sat there at several hundred degrees celsius, would this be preferable to continuing to create vast quantities of contaminated water? Any experts here know the answers?

It appears that the crisis stage of this accident is over and Japan is left with 3 melted down reactors in damaged containments.
Are any plausible estimates now possible of the amount of radioactive material dispersed?
Presumably all of the noble gases are gone, but the iodine and cesium may still be largely in the 100,000 tons of water swamping the plant.
The extent of the long term land abandonment will be determined by this.

Thanks @uvdiv for supplying link. As I stated I support nuclear but as someone who has been in the uranium business for 25 years, i believe it is important we move beyond the preaching to the converted traps. BLOGs have been wonderful for confirmatory bias. This accident has had an unacceptable consequence in relation to spread of Cs137 in a land poor country. We also know that for a significant part of this crisis winds were offshore. What if they werent? What if winds were northeasterlies? Think about this from a Japanese regulator’s perspective. I believe nuclear is a technology we cant walk away from but we need to take a whole new look at reactor design ( yes I know Gen 3 are better but still require an element of trust if you are a regulator) and how we debate the issue. If you are pro nuke first acknowledge this has been a bad accident with serious long term consequences then build your argument from there.

Thanks Andrew for links particularly to the wakeford article which is a ripper. Again, from a Japanese regulators perspective you would be gun shy about nuclear if you consider another accident with more persistent on shore winds. To me the hydrogen explosions have contributed to the spread of contaminants. Are there ways to reduce this risk in terms of retro fitting old plants? Also fuel ponds have been overlooked. These have possible contributed a significant amount to NW trending contaminated zone. Would need to check wind directions with accident chronology.

@etudiant; I’m not calling crisis over yet. The cooling for the three damaged reactors is not looped and the internal status of the reactors is still highly unclear. The spent fuel pools have come off the danger list, although buliding damage is still a possible concern in the event of further earthquakes. So precaution is still a reasonable position.

I don’t really see – under current radioactive dispersion – that there will be any long-term land abandonment. The power plant itself is the most contaminated ground, of course, but that is not likely to spread contamination elsewhere, except the sea. The best use for that land is another couple of reactors!

“To me the hydrogen explosions have contributed to the spread of contaminants.”

Indeed, the venting of radioactives gases into the environment might be another important source.

I wonder if we could use air balloons to store the radioactive gases (instead of venting into the atmosphere), or some seawater tank to scrub and condensate the gases. Too bad we didn’t have any portable stuff like that [2].

Regarding the hydrogen issue, I am thinking about silicon carbide cladding [1]. That would be so wonderfull. Unfortunately, it might take a while before it happen.

“The water level in Unit 1 is believed to have dropped much faster than for Units 2 and 3.

Why would this have occurred in Unit 1 and not Units 2 and 3? It’s possible it was due to whatever specific damage was caused by the earthquake and tsunami. A recent press story suggests instead that a worker may have shut down Unit 1’s cooling system shortly after the earthquake hit, causing the water to quickly boil away.

But Dave Lochbaum notes that Unit 1 had a different “water makeup system”—which is used to keep water levels where they should be—than Units 2 and 3. Moreover, even if the cooling system had not been shut off by a worker, it would have failed shortly on its own.”

Venting was the primary cause of radionuclide release; but the hydrogen explosions helped throw them into the wider environment.

Does anyone know more about the venting/stack systems? US BWRs changed the vent path from the top section of the building to a hardened external vent so that even if hydrogen was present and there needed to be venting, there would be no building damage. I would like to know what kind of filters they use for the vent stacks. Carbon filters, resin filters, aqeous acid solution bath scrubbers? I’m quite amazed at the large quantity of cesium that escaped, this should be much lower with good stack filter systems…

— the usual “venting” system that draws air out of the building, through a variety of filters (the system that keeps the whole building at slightly lower air pressure). A proposed alternative “sand filter” was suggested decades ago but never built.

— the emergency “vent” system (direct release, no filters) intended to release pressure from inside the reactor pressure vessel, that failed on all three reactors for several different reasons (tried too late, no power, valves too radioactive to turn manually, valves failed to work).

“… this handbook addresses systems and equipment used in nuclear facilities to capture and control radioactive aerosols and gases…. not intended for application to commercial systems other than for general historical information and discussions of basic air cleaning theory. …

CHAPTER 1 HISTORY OF THE DEVELOPMENT OF AIR CLEANING TECHNOLOGY IN THE NUCLEAR INDUSTRY ….”

http://dx.doi.org/10.1016/0029-5493(90)90286-7
“… concerns that BWR MK I primary containment integrity would be lost should a significant mass of molten debris escape the reactor vessel during a severe accident.
… major factors influencing secondary containment effectiveness include: the mode and location of the primary containment failure, the internal architectural design of the secondary containment, the design of the standby gas treatment system, and the ability of fire protection system sprays to remove suspended aerosols from the the secondary containment atmosphere. Each of these factors interact in a very complex manner to determine secondary containment severe accident mitigation performance.
… plant-specific features that could influence secondary containment severe accident survivability and accident mitigation effectiveness. Current issues surrounding secondary containment performance are discussed ….”

The role of BWR secondary containments in severe accident mitigation: Issues and insights from recent analyses
Oak Ridge National Laboratory
December 1988

“…. The new information revealed greater-than-suspected damage and disclosed, for instance, repeated attempts to open pressure-release safety valves. Vents remotely did not work, presumably because of the power outage.

At least two attempts were made to open valves manually. But the company data offered no other details ….

The failure of the manual attempts could indicate an even greater breakdown of the system, but Nuclear and Industrial Safety Agency official Yusuke Terasaki would point only to power loss in explaining the venting problem…..”

“… almost 30 percent more intensity than it [one of the reactors] had been designed to withstand, raising the possibility that key systems were compromised even before a massive tsunami hit …
…. partial data recovered from the crippled Fukushima Daiichi plant showed the ground acceleration during the quake exceeded its design specifications at three of the six reactors.”

They don’t say which three; I’d guess #1, #2, and #3, the oldest ones. It would be interesting to know how the design spec differs for #4 and later reactors.

Just to make certain it is understood what has to happen for a breech of the containment (most likely to the ground underneath the reactor building and possibly into the ground water in the area-if actually possible… not saying it is)

the fuel has to melt and collect on the bottom of the RPV in sufficient amounts to cause melting of the inches thick stainless steel RPV, then hit thru a foot or more of reinforced concrete?

The emergency steam venting seemed to work fine; the design flaw was in venting to the top building section. The idea is to hold up radionuclides there, but obviously if there’s hydrogen that provides an explosive hazard. US BWRs have changed the vent path to an external hardened vent so that this is not risked.

If there are no filters on the emergency steam venting stack then that is a serious design flaw. I’m having trouble believing this. A simple aqueous HF scrubber bath for example can remove 99.9+ percent of the cesium. Combine with carbon filters, resin filters and cloth filters gives superiour protection. Shouldn’t be hard to design a filter system that removes 99.99% of cesium and iodine. This is all passive operation – the high pressure steam just passes through the vent line with all its filters on the way out.

Cyril, where did you find a “design … venting to the top building section” described? I thought that the vents went out above the rooftop — but weren’t used, so hydrogen accumulated because the operators didn’t or couldn’t get the vent system to operate early enough.

“… actions should be taken, on a generic basis, to reduce the vulnerability of BWR Mark I containments to severe accident challenges. At the conclusion of the Mark I Containment Performance Improvement Program, the staff identified a number of plant modifications that substantially enhance the plants’ capability to both prevent and mitigate the consequences of severe accidents. The improvements that were recommended include (1) improved hardened wetwell vent capability ….”

Harry, do you know — out of the four or six reactors — which ones are the three with the lower rating for earthquake? Do they show how close the actual measured motion was to the design rating for each reactor?

At that PDF you linked May 2011 at 12:39 PM, I see only this:
東京電力株式会社
現在、サーバ障害によって、つながりにくい状況となっております。
皆さまには大変ご迷惑をおかけいたしますが、しばらくお待ちくださいますようお願い申し上げます。
(C)TEPCO

“… In other news… TEPCO has further increased the rate of water injection to the reactor at No. 3 plant at the Fukushima Daiichi site. TEPCO is now injecting a total of 21 cubic meters per hour to the plant; 9 through the fire extinguishing line and 12 through the feed system. Prior to today, the rate had been 18 cubic meters per hour….

This continuous increase is of interest; also of interest is the injection of 180 kg of boric acid on May 15th from 14:33 through 17:00. Soon after this, there appears on the temperature tracking graphs released by TEPCO a sharp rise in a number of temperatures, particularly those at the top of the RPV but also at least one related to a downstream (tailpiece) temperature reading on a steam relief valve. There was also a drop in RPV indicated water level that this increasing of feed rate has corrected.. the drop in level occurring before the borated water was added. I’m both looking for more details on this and waiting for another TEPCO press release that might mention their thinking.. and their suspicions.”

Question for Barry (for your nuclear expert you menetioned who said he thinks the leaks are probably bad seals) — would the seals be expected to continue to deteriorate over time once they start to leak? Would more of the seals be expected to break down if there’s melted core on the bottom of the RPV?

I’m wondering where the excess water has been going and why adding borate is being done now, and whether they’re stuck pouring more and more water into the leaking system until they can find some other way of cooling things down.

Why not start bringing in liquid nitrogen? Or would that risk cracking from sudden cooling shock?

Ah, this has details for Japanese reactor designs going back to Fukushima — noting changes over time. This includes the ground earthquake motion specifications, which have changed over time, and mentions geology details for sites as well.

There are also occasional interesting tidbits under the ‘press handout’ and ‘photos for press’ link pages of the fukushima status page. I.E. The 10,000 cubic meter ‘megafloat’ and the components for a cooling system have arrived.

My background: engineered 24 years nukes, including 9 like Fukashima ( BWR Mark I), also Mark II and the prototype Mark III, initially in structures then including in systems. I headed the first US dry cask storage facility engineering team and was debriefed, and knew key engineers involved with the TMI and Chernobyl events (One was not an accident, it was blown up to prove to engineers that all those pesky safety systems were nonsense.) I know nothing about Japanese designs.

My judgments: TEPCO’s slow, weak response in the early hours after the quake/tsunami, and the lousy design of the DG emergency systems doomed the plant. I am dumbfounded how little, and uncertain the present level of knowledge is, but it tracks TMI and Chernobyl. After the inevitable management /possibly government purge we will learn more.

My (wild) guess: U1, U2 and U3 have melted cores. The earthquake ripped two primary containments (the steel light bulb and doughnut shaped pressure vessel) open. The U4 spent fuel pool structure was broken by the quake. There is a real danger that a subsequent after shock may (a hated word to nuke engineers) cause catastrophic damage, e.g. drop the U4 spent fuel pool inventory on the ground. Spent fuel is heaver than lead and those pools are crammed with SF. Know that it is hideously lethal, its radioactive energy is barely reduced, only the “tin can” is spent in material properties. Nations who store lots of spent fuel in pools for long periods of time do so because of politics. Earthquakes make pools leak. And wiggle piles of melted fuel, which might cause a uncontrolled critical mass, awake the monster where ever he is.

And a 250 KPH Typhoon would be unkind.

Fukushima is in a meta stable safety condition.

After forty years of engineering, ending in a decade assessing advanced technologies: what is coming, what are the barriers, and when will they be real, I conclude that well engineered, built and operated nukes are vital to mankind’s future development, along with fossil fuels, particularly coal. The green energies always cost too much; they will beggar any nation would attempts base loaded supply. But the real barriers to safe nuclear energy is politics, both corporate and government. Neither convey the truth.

R.L. Hails, you should distinguish between the higher up spent fuel ponds of older BWRs and below grade pools. The latter don’t break or leak catastrophically under any torment, because they are already below grade. Putting spent fuel pools 20-30 meters plus high up in a building is a serious design flaw. The central spent fuel pool at Fukushima is fine though – its built as it should be, below grade. If we want to keep using higher up spent fuel pools in existing reactors then my engineering advice is that they will need multiple hardened spray cooling connected to standpipes on the ground, so that easy access cooling from the ground is always available. Passive hydrogen recombiners and igniters above the pools and you’re all set for safe operation.

The elevation of the spent fuel pool, relative to grade, and the reactor flange, was one of the key decisions in the progression from the Mark I , II, and III designs. Among the several aspects to consider, was the safe transport mode of a spent fuel assembly from the reactor to the pool (horizontal, vertical, or inclined) and the seismic loads of a heavy pool high in the structure. This elevation decision is significantly influenced by the bottom control rod design requirements of BWRs. A core melt down in a BWR is new to mankind, because of this complex geometry.

However, my point was the policy of maintaining a massive inventory in the pools, which were never intended in the original fuel cycle design. The US pools are crammed with spent fuel because the government has breached it’s legal obligation to take the spent inventory. Spent fuel takes several years to cool off, after reactor excitation, and significant pool cooling is required during this time, particularly, as with Fukushima U4, in which a full core was off loaded to permit reactor internal repair work. Japan allows spent fuel reprocessing which is verboten in the US, yet for reasons unknown to me, the plant holds 6,000 + tons of spent fuel in an active earthquake/tsunami zone. That is bad engineering.

I would disagree that seismic forces could never cause a pool to leak, whether elevated or not. From media reports, there is significant concern about the seismic integrity of the U4 spent fuel pool, vulnerable to large after shocks. Some leakage is acceptable in the pool liner design and make up systems, but there is no back up for gross pool failure, at any elevation.

We can not speak of safe operation at Fukushima. They blew safe operation.

“Japan Nuclear Fuel Ltd. has decided to delay the start of full-scale commercial operations at a spent nuclear fuel reprocessing plant in Rokkasho, Aomori Prefecture, by two more years to 2012. This, the 18th postponement of the project, will leave it 15 years behind schedule. The plant was originally slated to begin operating in 1997….
…
… The project to develop the fast-breeder reactor needed for the envisioned nuclear fuel cycle was given a lift when the Monju prototype reactor in Fukui Prefecture resumed operations in May, for the first time in 14 years. But it soon encountered problems. It has not even been decided whether the electric power industry or the government will build the demonstration reactor planned as Monju’s successor….”

“… Monju was being built by different companies working together, Hitachi, Toshiba, Mitsubishi, Fuji Electric, etc.

When they drew up the spec, Hitachi, where I used to work, would round down 0.5 millimeter. Toshiba and Mitsubishi would round up 0.5 millimeter, Nihon Genken would round down 0.5 milli-meter. It was only 0.5 millimeter, but it made a whole lot of difference when there were 100 different parts that needed to fit together. So the pipes didn’t fit, even though they were exactly to the spec and fit perfectly on the blueprint….”

Following recovery of the device which was used for fuel exchange, the agency plans to restore operations at the 280,000-kilowatt nuclear reactor to the pre-mishap level and start a test run of 40 percent output of it by the end of fiscal 2011 through next March….
(Mainichi Japan) May 11, 2011

“… we have been evaluating the seismic capacity to confirm the soundness of the building. As the result of the evaluation, we have decided to install support structure under the spent fuel pool to enhance safety of the building.

■Work Overview

– Install steel support under the spent fuel pool to sustain the weight above

– To secure its function, install concrete wall and fill up grout between the concrete wall and the bottom of the spent fuel poll

■Schedule

We are now developing detailed work plan and plan to start the preparation work from early May. Then, we will start the main work from mid-May and complete it at the end of July. We expect to finish the installation of steel support by mid-June. Thereafter, we can anticipate that the load will be decreased….”

The information, particularly the hyperlinks, from Hank Roberts is both insightful and has parrallels with US experience. He discusses a disaster, the lack of interchangeable piping due to a lack of enforceable national technical standards and a management organization with little or no technical expertise. I point out that a group of high level BP executives was on board the drilling rig in the Gulf of Mexico one year ago, and not one person recognised that they were minutes away from roasting in an inferno. Hanks’ article notes the 18th postponement of a highly technical prototype project, 15 years behind schedule, culiminating in the accidental dropping a 3 ton object into the reactor, and calls for help to retired experts. Some US nukes have worse records. The US DOE spent fuel storage facility, Yucca Mountain, was scheduled to accept shipments in Jan 1998. Built for some $40 Bn, it holds nothing.

I met with experts in reprocessing in the mid 1980s. It is far more complex than rocket science; the experts in the field were the cream of their graduating classes. My guess today: most are dead, or retired. I know many lost their careers. It is not possible to hold a brilliant team together for decades, while producing nothing. Only a buracracy would try. Compare the rate of progress of the technologies among reprocessing, bioengineering, robotics and electronics over the last three decades. Compare the technical talents in top management amoung TEPCO, Microsoft, Google, and the Predator drone operation organizations. How did each organization respond to rapid technical change and risk? Do they exhibit robust technical expertise; is each, “on top of their game”? In plain language,does the current nuclear power industry know what it is doing, e.g. in fuel reprocessing, tsunami protection, or hydrogen explosion systems? It has done very little in several generations. Why would any bright youngest go into this career field? In 1980? 1990? 2000? or 2010? What happens in twenty years, if they do not.

At my level of comprehension of the Japanese culture, this may be the root problem of the Fukushima disaster. Japan is not unique in this societal – technical miasma.

R.L. Hails, my point was not that pools can’t leak, the point was that if the pool is below grade then catastrophic leakage can be prevented; the pool being below grade there’s nothing to rapidly leak away to! Cracks and stuff is still possible, but very easy to deal with that, you can use simple clay packing around the pool for eartquake protection, and everything is always easily accessible from the ground. Plunking in a firehose is all you need to do in a worst case scenario. That’s very hard if the pool is a hundred feet up in the air!!

Holding spent fuel in eartquake zones isn’t bad engineering; its bad engineering itself that leads to trouble. For example the dry casks and central below grade spent fuel pools are fine. They are well engineered.

Putting spent fuel high up in spent fuel pools in the reactor building itself is downright stupid. I’ve talked to a nuclear engineer about it and he said it’s the only thing he disliked about the early GE BWR designs (and he’s a PWR operator mind you!)

As for the Monju reactor, from what I understand its not a very good design. Oxide fuel, fast reactor sodium coolant. This is not a good combination. Fast reactors that breed need to reprocess their fuel, which is expensive with oxides. You also need fuel that dilates sufficiently upon heating to control fission. Metal fuel or molten fuel would be needed to get that, and also get easier, cheaper reprocessing.

Thank you for the insights. As well as the ability to maintain technical capability affecting safety performance I also wonder whether there is also a fundamental inability to learn shown in the Fukushima.

A couple of points are of interest to me which your experience might help give an authoritative answer to:

1) Learning from TMI and other US incidents. My understanding is that various modifications were mandated to US installions (redundancy of cooling systems particularly) following TMI, other incidents and a post 9/11 review. Further that these were not implemented at Fukushima. Is this correct, and if so, what’s your belief as to the difference this would have made to the outcome?

2) Hydrogen venting. The current TEPCO hypothesis seems to be that backflow of hydrogen from the emergency vent ex unit three entered unit 4 causing the explosion there. This seems to me to be an absolutely fundamental design error and again, one which has been well understood elsewhere in the nuclear and process industries.

My perspective is that a culture of secrecy and desire to reassure have prevented learning. Fundamental change in the openness of the industry is, I think, required to even make it possible to contemplate a change in public perception.

Brian touches some excellent points on nuclear disasters. Much of our judgments stem from the TMI experience. The Governor, Richard Thornburgh, faced a novel and agonizing set of decisions, immediately after the accident (a stuck open valve and horrible operator performance) due to bum info. The plant instrumentation, common to US plants, was very precise over a small range. It’s purpose was control. However, the words of the first engineer to enter the control room are seared into my memory; he said it was like entering the cockpit of a 747, at 45,000 ft, looking out and not seeing any wings. What do you do? Nuclear experts were advising the public safety decision maker, screaming that everybody was going to die; others heatedly said there was no problem outside the containment. Thornburgh asked who, in the population is most vulnerable to radiation? Infants in the womb, and babies; both are undergoing most rapid growth. With zero technical knowledge, and national terror, he advised expecting moms, and infants to pull back ten miles. This became dogma, a much debated conflict at Fukushima. The real answer is not to let the crap get out, but if air borne zoomies exist, look at a wind rose. If a typhoon hits those open, or weakened pools, God help Japan. The lethal inventory contains half-lives of 10E6 years. Barring storms, or more quakes, they are metastable.

(Cyril R has a very smart friend.)

After TMI, all US plants stuffed (back fitted) redundant wide range instrumentation systems, e,g, to define if the containment was dry, half filled with water, or flooded to the top of the core. We know you can not go in and measure; you must know the plant condition during and after an accident. The ignorance, today, at Fukushima blows my mind. Or the cover up. They appear to be back calculating varying isotopes, of varying half lifes, which must come from a fission reaction, and
“swagging” conditions, just like TMI. But I am ignorant; I do not know what instrumentation exists or is working. I am certain they are under life threatening emotional stress.

One day into the accident, TEPCO had sealed their fate; 80% of their assets vanished, and some $300 Bn in liabilities exist. Had they known ten years ago, would their management decision making been different? Mankind has learned a thousand fold more about subduction quakes, tsunamis, and wide range instrument loops, since U1 was designed. They reportedly took two weeks to string 1/2 mile of power cable to restore plant power. Should a redundant cable have been hung 25 years ago? What was technically decided? By who? What motivated him?

If the peaceful use of nuclear technology is to contribute to society, Brian’s point is axiomatic. It requires brutal honesty of experts, including the open humility to say, “I do not know”, and the political guts to tell voters that all energy can kill, risk will always exist. This requires never ending technical excellence, the highest ethical standards of profit seekers, and politicians, and recognition of those who sustain an advanced way of life. These societal traits, not the complex technology, are the current barriers to “safe” nuclear energy, climate change, and most technical controversies. High voltage is unkind to dumb, greedy people. So is radiation.

Rainy season in Japan is in June and the area is mountainous. There is a possibility of some movement of contamination due to rainwater runoff.

If I was the minister in charge I would wait until after the rainy season before I made decisions about which areas can be re-inhabited without mitigation, which areas will be mitigated and which areas will have long term land use restrictions.

R. L. Hails, lethal inventory and million year half lives is oxymoron. Isotopes with million year half lives are not very radioactive, and not dangerous to health.

Take iodine-129. It’s radioactive and fission produces a bunch of it, but its long half life makes it, atom for atom, eight hundred million times less radioactive than iodine-131. The difference between dangerous to health and laughable. Worry more about natural uranium in the environment – which is literally everywhere!

People don’t see the difference. Radioactive is radioactive, to them. They don’t know anything actually relevant such as biological uptake and bioconcentration, or the large quantities of natural background radiation that have zero effect on health.

Regarding ‘safety culture’ I don’t like that kind of thinking. People make mistakes. Training and procedures help, but are not foolproof. I much prefer simple, redundant, diverse and passive technical solutions to risks. A diesel generator on the top floor, passive hydrogen recombiners, a hardened external overpressure steam vent with loads of gasket-less carbon filter beds, a two month submarine grade lithium battery system for essential controls and valves, and you’re all set to go.

As for energy being deadly, this is unfortunately true. But nuclear and hydro are the least deadly (wind requires loads of deadly fossil backup or deadly chemicals and material mining for batteries, making it more deadly than nuclear on the system level). Most importantly burning stuff is extremely deadly. Even biomass is dangerous – an order of magnitude more so than nuclear or hydro.

My apologies, a typo with a phone call. strike 10E6, insert 10E5; this error does not change my argument however.

I have witnessed one spent fuel assembly coming out of a transport cask, through ten feet of leaded glass, quickly. The cameras burnt out their electronics and the rad meter pegged at 17,000 R. Death would be certain after a few minutes in that field, although it would take weeks to yield up the spirit.

I led the first US dry cask engineering effort, put the spent fuel in 125 ton garbage cans, nominally 1 foot thick steel and triple sealed, with deep full penetration welds. “Dry” means no heat producing moderator, water. The fuel sits in an inert gas atmosphere to prevent adverse chemical reactions. There are systems which counter act hostile actions which I will not discuss. The alternative approach is to reprocess (repackage the energetic fuel). and reuse it. This back end of the fuel cycle is a political football in the US, and has created a massive societal danger.

I will not quibble buzz words. To allow this lethal material to sit in open pools, or dry casks, scattered about a nation, for generations, is not a safety culture. Fukushima holds circa 6,000 tons, the US inventory is circa 70,000 tons. Most spent fuel should rest in one central below ground tomb, monitored in 3D by advanced surveillance systems, with military might nearby.. To do otherwise is to invite biblical disaster, from skilled enemies. It is lousy technical management, lousy politics, lousy security.

President Roosevelt faced a similar problem when world war was eminent, a fear that the Nazi could steal our scattered gold reserves along the east coast. In ninety days, he moved it inland, and buried it under the fourth armored division, in Fort Knox Kentucky. Not a gram has been disturbed.

I can guess how the decision to place the emergency electrical system below flood level occurred, when at modest cost, it could have been designed above any uncertain flood level. I can guess how an operating DG ran out of fuel since no one filled the tank. I know you can not store emergency electricity in sufficient amounts to control a nuke, I do not understand why a fleet of ships, from one of the largest, most modern ports on earth, Tokyo, did not sail at combat speed to the crippled plant, when hours could have saved everything. Photos the next morning showed an empty shoreline; an armada of fuel/ water tankers, repair shops, and skilled worker accommodations, should have been moored to prearranged berths, everything preplanned, staged, and rehearsed years ago. What is still at risk is a large portion of their nation. With 20-20 hind sight, the technical management decision making at Fukushima has been tardy, inept, and costly. The entire world waited for one concrete pump truck to be air freighted across the Pacific, to that plant, while the pools appeared to be boiling. The robots being used are ad hoc designs developed in New England. These are the droppings that reveal lousy technical management. I do not think it is unique.

Robotics is a game changer in lethal environments. Thousands are used in combat, none are engineered into nuclear power plants (I am not current in this assessment.). The most effective mine field clearer on earth is a 70 ton US main battle tank which is run by a remote joy stick. A variant, engineered for high rad areas, could reduce cesium contaminated soil to a manageable nuisance, but the R&D funding levels are orders of magnitude different between these two dangers.

Nevertheless, properly managed, with talent, and ethics, nuclear power is the technical way to go for modern societies.

Nonsense, dry modular storage is far more effective and secure than putting the stuff underground in a tomb.

Sometimes you’re not making sense, Hails. 10000 year half life is not dangerous at all, you are referring to the short lived stuff. Yes that must be remotely handled – because of half lives of under 30 years, especially the stuff under 1 year half life yes is dangerous to even look at in the kilograms plus quantities that these are indeed present in spent fuel.

I’m also an environmental and safety engineer. Putting stuff underground is a recipe for disaster – far more than modular dry cask storage which is easy to access at all times. I recommend against all underground waste disposal except for the longest lived radionuclides (they’re not more dangerous than natural uranium that is in the ground). Societies around the world are currently storing dangerous coal ashes in underground mines very primitively, and the coal ash is just as toxic in a million years from now, unlike spent fuel.

The subsoil is not something you go into willingly. It offers no advantage over multiple layers of engineered barriers (stainless steel, steel, reinforced concrete) and there’s always a risk of ground contamination if you build a tombe and abandon it. If you’re uncertain you use more concrete and steel. After about 300 years all of the short lived stuff is gone and you’ve got a goldmine of stable isotopes and high value fissile. Actually I believe we’ll remove the fissile and many other isotopes much earlier than 300 years because we’ll want them so badly to start up Gen IV reactors and for a variety of medical and industrial catalyst applications. I very much doubt we’ll end up waiting even 100 years. We’ll need all the transuranics we can get to start up terrawatts of advanced Gen IV plants.

As for Biblical disasters, no nuclear even will ever do that. Old spent fuel that sits in a dry cask is just not going to do it. The thermodynamic driving force to throw out radionuclides just isn’t there, and its well protected in multiple layers of stainless steel, carbon steel, and reinforced concrete, all in a simple passively cooled arrangement.

Try continued increased burning of fossil fuels for centuries and you’re much nearer a Biblical event. A hundred years at today’s GhG emissions is about 5 trillion tonnes of CO2 equivalents. Wanna see if that’s Biblical?

No, not ignoring it – the equilibria concentrations are are very small. If it weren’t, natural uranium would be very dangerous. Fissioning actinides away actually reduces the long term radioactivity, because of the decay chain induced actvities you mention. It just doesn’t really matter, after a couple centuries you’d have to eat a lot of it to get killed.

However the U-Pu cycle does make more transuraniums than the Th-U233 cycle, which gives thorium an edge in this respect:

Basically the fission products are the big danger for fresh spent fuel, but they drop below natural uranium rather quickly. Its the transuraniums that give long term activity and hence storage requirement (their decay products are only a minor compounding factor), but fortunately they burn very well in thermal and fast Gen IV reactors such as MSRs and IFRs. This is because they are very heavy elements that are unhappy being so fat.

You do see some bumped up behaviour for the accellerator driven system, which is related to the ingrowth of new nuclides by decay as well as peculiar spallation products forming.

Kirk Sorensen has some nice Java applications on spent fuel and isotope decays.

We are not communicating for several reasons. I am busy but, after forty years of rigorous technical communication which passes over the heads of most decision makers, and readers, I lower the rigor. And rightfully get rocks from technical experts. So be it.

You are both correct and wrong.

The initial concept of the tomb was to store spent fuel in retrievable, controlled geometry dry casks (not buried in pits) and place them in a “permanent” deep underground cavern, a stable mountain. As long as the fuel is stored behind multiple, militarily protected barriers, we are safe. The casks were initially meant to be buffer storage, temporary storage facilities, to accommodate fuel management needs: utilities, and the DOE repository functions. This reasonable approach was trashed, in the US, due to the Yucca Mount fiasco, and vested interests who forced two types of casks (and multiple fuel handling): storage casks, and transport casks. The less you handle fuel, the safer you are.

The policy error is ubiquitous, distributed, long term on-site storage, either in casks or modular storage structures. This is where we are, a very very bad idea. You want a mountain over the casks with a entrance door only our government (or a sane government) controls.

Where we may disagree is the effects of natural, uncontrolled dispersal of spent fuel particles, “fall out”, e.g. driven by a typhoon, over vast land areas, with NO barriers to the environment. Japan, today, is vulnerable from Fukushima, due to its heavy inventory of exposed unprotected spent fuel. The people of Hiroshima and Nagasaki well know the biblical dangers of fall out. ( It is impossible that spent fuel, untreated, could cause an A bomb explosion, but it is quite possible to cause a mess.)

I share your judgment that a different US polity on reprocessing will change the value of this waste to a national resource, aka better than Ft Knox’s gold, within this century. It must be retrievable for that purpose, and would be, sitting in underground casks.

Our discussion on CO2 must wait for another venue. My time is limited.

RL Hails; Perhaps it’s a lack of imagination, but I don’t see the threat of spent fuel casks. In order to conjure any problem I would have to ignore the nature of the casks and indeed of the fuel. We are not looking at anything that is easily dispersed here, even by significant forces.

Fukushima spent fuel is apparently not as badly protected as was feared; nevertheless, they might well have been better off with more use of casks.

Incidentally – the people of Hiroshima and Nagasaki really didn’t have a significant amount of fallout from their bombs. They were killed by blast, fire, and direct irradiation. Fallout was not a major factor, which is one reason I find the comparison of nuclear power accidents to the fallout from those weapons annoying.
Biblical? as believable as Noah’s flood, I guess… but I fear that discussion would be too far off topicMODERATOR
Joffan – please supply refs to support your assertions above. Future comments will be deleted without them

Hello to all, I have been following this blog since the March 11 quake and It has been or great help in providing information about the situation and also by giving opinions from some more in the know when it comes to nuke power. However I fear Japan is headed for another Nuclear disaster in Fukui Prefecture. The Monju power plant is a experimental Fast breeder reactor that has many problems. The latest is the fact that a 3.3 ton machine fell into the reactor during schedule refulling. The company has tried 24 times to revcover the machine without success. The now plan to do something different that I have hear may cause and explosion that in worst case will be a reactor explosion due to the sodium coming into contact with water??. I would be greatful if any on here know or can provide information on the situation at Monju. They began this operation today but there is very little info out there. Thanks in advance.MODERATOR
John – this is a science blog and as such the policy is to require refs/links to support your comments. Please supply links to your accounts of what is happening at Monju. Further comments without refs may be deleted.

Work to Start for Removing Jammed Gear from Monju N-Reactor
Fukui, May 23 (Jiji Press)–Workers will start preparations Tuesday to remove a piece of equipment that jams in a prototype fast-breeder nuclear reactor in central Japan, officials said Monday.
Workers at the Japan Atomic Energy Agency will install devices necessary to pull the 12-meter-long, 3.3-ton in-vessel transfer machine out of the Monju reactor in Tsuruga, Fukui Prefecture.
The machine, used in refueling work, has been stuck in the reactor vessel since an accident in August last year.
The removal work is expected to take place in mid-June after the agency gets the go-ahead from the industry ministry’s Nuclear and Industrial Safety Agency, the officials said.
The agency hopes to complete all related repairs by the autumn.

I’ve never seen any mention of 24 attempts to retrieve the equipment however, and prudent precautions will be used to avoid any sodium-water contact (e.g. inert atmosphere, and the primary loop is not connected to the steam generator anyhow).

That said, Monju is an example of how NOT to pursue a commercial fast reactor, as Cyril noted elsewhere. For a start, the oxide fuel and loop design are just the wrong ways to go for sodium-cooled fast reactors; the US went there, did that (with CRBR and others), and then turned their focus to the metal-fuelled pool-design IFR (EBR-II), which ran flawlessly for 30 years.

At that level, “public health measures” are not necessary except perhaps in the red zone on the map.

Which suggests that the exclusion zone is only necessary because of the risk of new emissions rather than existing levels.

2) Longer Term

According to Wikipedia, Chernobyl “Closed Zone” is set at 40 Ci/km2, which (I think) is 1.5e6 Bq/m2

On the MEXT map, Cs 137 peaks (red zone) at 3-14e6 Bq/m2, 80-380 Ci/km2. This is higher than the Chernobyl “closed zone”. Note that the Cs-137 deposit “red zone” is very similar to the overall dose red zone. I guess the choice of ranges leading to this isn’t a coincidence.

Which suggests that, unless my calculations are wrong (entirely possible) there is a real likelihood that a substantial part of the current exclusion zone will be long term uninhabitable, unless levels drop.

These conclusions don’t really seem consistent to me and where this goes seems to me to key to how serious the incident consequences are. I’d appreciate comments from those more knowledgeable than myself as to the errors or otherwise in this analysis.

R. L. Hails, with all due respect, we are not communicating because you are wrong on the danger issue. Old spent fuel does not pose any meaningful hazard to future generations; its fresh spent fuel that can be dangerous, but only in horrible designs such as 100 feet high pools with no redundant hardened standpipe connections to spray cool the fuel. This is what Fukushima shows: fresh fuel is potentially dangerous, old fuel in dry casks or below grade pools is very safe.

And while we continue to have the same debates about nuclear safety over and over, 2 million people die every year due to fossil fuel combustion.

You experts aren’t helping by dramatising the situation. Some people say we live in a risk averse society. This is not true. We live in a risk-deluded society.

“Regarding ‘safety culture’ I don’t like that kind of thinking. People make mistakes. Training and procedures help, but are not foolproof. I much prefer simple, redundant, diverse and passive technical solutions to risks. A diesel generator on the top floor, passive hydrogen recombiners, a hardened external overpressure steam vent with loads of gasket-less carbon filter beds, a two month submarine grade lithium battery system for essential controls and valves, and you’re all set to go.”

I agree with you that inherent safety is preferred and passive systems are better than active.

However, I would absolutely disagree that this obviates the need for a strong safety culture. Without a safety culture learning from other plants will never be implemented to fit such systems (eg Fukushima) and safety systems will not be adequately maintained (eg Buncefield and many, many others). Inherent safety and passive systems are necessary, but not sufficient. Without much more openness from the industry, this safety culture can not be delivered IMHO.

Hi Barry, and others on the blog.
Thank you for the speedy reply, and to the mod man sorry for not posting links I have added some to the end of this message which confirm what i said in my earlier post. Barry, and others on the blog, what do you think the worst case could be with the work going on at Monju? My wife seems to have found a load of information (in Japanese) that says it is a very dangerous operation they are attempting. (no ref for this as it is what I have been told) I hope the extra information in the links below may help. Thank you
John

As the 2nd story you linked to said, they are working in an inert argon atmosphere. There is no danger of an accident as the reactor is not operating and there is no water present or anywhere near. However, they may need to drain the sodium if they cannot retrieve the relay cylinder. That is the worst case — that the reactor restart will be delayed again, perhaps for another year (I’ve given up guessing when with Monju). In my honest opinion, the sooner the Japanese close down Monju, dump the loop design and move from oxide to metal fuels, the better. All they need to do is support a PRISM demo. Monju gives them plenty of additional reasons to do this!

You and Joffan and others keep saying this kind of thing over and over, with no science cite, just PR stuff.

I wonder how it gets by each time it’s repeated.MODERATOR
You are answering a comment in an Open Thread. Comments Policy is relaxed here, except for personal abuse, so references are not mandatory and personal opinion is tolerated.However, references to the hazards or otherwise of nuclear fuel abound on BNC posts.

Entrapment in large technology systems: institutional commitment and power relations

“… embedded commitments can create inertia, causing inferior technologies and technology paths to survive long after they should have been abandoned. This form of technological lock-in may be reinforced when there are close relations between producers and states which prevent markets and democratic processes from operating effectively. These phenomena are illustrated through study of the Thermal Oxide Reprocessing Plant (THORP) — a nuclear reprocessing plant in the UK. The lesson for technology policy is that much more attention needs to be given to the maintenance of reversibility and adaptability in infrastructural development…..”

“… the rationale for building the plant was predicated on securing a majority of its MOX fuel orders from Japanese utilities. No firm orders from Japan have materialised and none featured in the original order book ….”
and
“… the plant’s process system was too complex to succeed as projected (as admitted by the Secretary of State in 2008 – ‘SMP was based on unproven technology’), … and that hopes of securing large orders from Japan have virtually evaporated as a result of the loss of trust by Japanese utilities following the 1999 MOX falsification scandal.”

Incidentally – the people of Hiroshima and Nagasaki really didn’t have a significant amount of fallout from their bombs. They were killed by blast, fire, and direct irradiation. Fallout was not a major factor, which is one reason I find the comparison of nuclear power accidents to the fallout from those weapons annoying.
Biblical? as believable as Noah’s flood, I guess… but I fear that discussion would be too far off topic

(Just providing a reference for Joffan’s statement above.)

That’s correct about the fallout, though early direct measurements of radiation due to fallout from the bombs were very fragmentary, and estimates of doses from neutron activation and fallout were actually lacking in major early studies of the bomb survivors until the 1970s.

A comprehensive discussion of the dose estimates due to neutron activation and fallout
can be found in Chapter 6 of US-JAPAN JOINT REASSESSMENT OF ATOMIC BOMB RADIATION DOSIMETRY IN HIROSHIMA AND NAGASAKI: FINAL REPORT and is available here:

The maximal cumulative radiation dose from fallout integrated from 1 hour after the blasts to infinity
were estimated to be 0.01-0.03 Gy in the area of maximum fallout found to the northwest of Hiroshima and 0.2-0.4 Gy in a small area to the east of Nagasaki.

At the hypocenter, the estimated cumulative dose from neutron activation is estimated to be 0.8 Gy at Hiroshima and 0.3-0.4 Gy at Nagasaki.

The doses from neutron induced radiation are estimated to fall very rapidly with distance from the hypocenter, and they also fall very rapidly in time – some 80% of the induced dose being received on the first day after the explosions and 90% within the first five days.

Since essentially nobody was able to enter the immediate area of the hypocenters on the first day
after the explosion, it is extremely unlikely that anybody received more than 20% of the maximal accumulated dose from neutrons.

In contrast, the maximal estimated doses from direct gamma irradiation, received by people close enough to the hypocenters, but far enough away to survive the blast effects, that is, outside a radius of about 1 km at Hiroshima, were certainly orders of magnitude higher.

In brief, to stay on topic and scale a real disaster (scaling nuclear energy is most difficult, even for experts, but is vital).

An Hiroshima event is technically different from the latent danger of Fukushima in that some ~ 95% of bomb effects are released as heat/ radiant energy, perhaps 4% is released as fall out. However these explosions were ~ 1% efficient, and contained ~ 100+ lbs of fuel. (the real numbers are classified, unknown to me). Fukushima can not be a fission bomb, but it can undergo a steam/ hydrogen explosion due to a mis op and/or natural cause. Or hostile action. Pools can be drained and containers can be ruptured, thus removing vital shielding. Uncontrolled airborne releases can be thought of (crudely) as fall out. Power plant spent fuel inventories are orders of magnitude larger than any bomb. These facts are unarguable; they happened/ exist.

The danger of Fukushima is real, present, and can go really bad (my term; biblical). Spent fuel must always be under total control of governmental power. Japan does not have this today.

I have never heard, from any nuclear expert, that, “Old spent fuel does not pose any meaningful hazard to future generations.” If true, it would be the biggest technical breakthrough since Eisenhower’s Atoms for Peace. (You can carry fresh fuel in your pocket; it is harmless until it is excited by the fury of the reactor’s neutron flux.)

No society has properly scaled the risk of nuclear power. Our technical management policies are neither rational, safe, or sustainable. I honor this colloquy.

“”TEPCO is expected to submit a report to the Japanese Government today which will apparently assert clearly that there was NO damage to the reactor plants as a result of the Great East Japan Earthquake… The damage sequence began when the tsunami hit and triggered an essentially unrecoverable SBO accident scenario.””

Which suggests that, unless my calculations are wrong (entirely possible) there is a real likelihood that a substantial part of the current exclusion zone will be long term uninhabitable, unless levels drop.

The Chernobyl exclusion zone is some 2,800 sq km and the land was relatively low value. The Soviets chose not to mitigate.

If I eyeball the DOE/Mext slide then I guess an area of about 10km wide by 40 km long potentially needs mitigation.

Risk is simple. How many people die. Fossil fuels kill >2 million/year. How many will die due radiation from Fukushima? Zero or a few.

The simple fact you can’t argue about either, is that nuclear and hydro are the safest forms of energy generation. Oh sure dams ‘can’ burst, and reinforced concrete canisters ‘can’ burst but that doesn’t make them dangerous. Fossil fuels store their waste INTO the OPEN ENVIRONMENT *BY DESIGN*. This kills.

No offense but ‘experts’ such as you that can’t resist words such as “Biblical events” to describe old nuclear fuel that has no real threat in it are hurting the cause of our planet and our very own human development.

You experts much show perspective and be constructive in supporting and improving the safest and best form of energy we’ve got – nuclear fission.

An Hiroshima event is technically different from the latent danger of Fukushima in that some ~ 95% of bomb effects are released as heat/ radiant energy, perhaps 4% is released as fall out.

The total (mean) energy released per fission for U235 is 202.5 MeV.

This energy is distributed, roughly, as 170 MeV in kinetic energy of the major two fission products, 5 MeV among an average of 2.5 fast neutrons, and 7 MeV in prompt gamma rays, for a total of 182 MeV in promptly released fission energy.

The prompt energy release is what determines the explosive yield of the weapon, and it amounts about 89% of the total energy release per fission.

The other 11% of the energy appears as delayed betas (6.5 MeV), anti-neutrinos (8.8 MeV),
and gammas (6.5 MeV). The anti-neutrinos
interact only very weakly with matter. So that amounts to another 13 MeV per fission that is released over time, as ionizing radiation, either betas or gammas from the decays of the fission products.

Thus, if the only fuel is U235, then about 93% of the total energy release per fission, that could harm people and structures will appear as blast wave, radiant heat, and prompt ionising radiation.

A further 7% is in the fallout. But it is the distribution
of the fallout that really matters.

If most of the vaporised bomb material goes up into the stratosphere, as it does in an airburst at sufficiently high altitude, and as it undoubtedly did at both Hiroshima and Nagasaki, then the radioactive energy carried in fallout is not very relevant to the bomb’s effects on people.

So while your numbers are roughly right, they are also quite misleading.

The yield at Hiroshima has been estimated at 13.1 kt TNT = 3.420994604 x 10^26 MeV, which would result, using the above figure for the prompt fission
energy, to 1.689×10^24 U235 fissions, or the fission
of about 0.66 kg of U235. We of course don’t know for sure the mass of U235 that was used in Little Boy, but the mass of the spike plus bullet typically said to have been about 60 kg, probably enriched to about 90%, since at that enrichment a gun barrel design could work, with less than a 10% risk of predetonation due to spontaneous fission of U238.

That I believe is the source of the oft quoted 1%
efficiency estimate for the Hiroshima bomb that
you repeat. The Nagasaki bomb was considerably more efficient and certainly used a far smaller mass of plutonium.

But all of these considerations are essentially irrelevant to the situation at Fukushima.

Fukushima can not be a fission bomb, but it can undergo a steam/ hydrogen explosion due to a mis op and/or natural cause. Or hostile action.

Chemical explosions due to hostile or other causes are theoretically possible, of course. But such statements aren’t very convincing without giving specific scenarios under which such things could very widely disperse a great deal of the fission products contained in the fuel pellets Remember that people have been evacuated out
to pretty significant distances from the plant.

It seems to me that the more worrying scenarios with respect to fresh spent fuel involve the potential for overheating due to residual decay heat with possible uncovery of the fuel, and the resulting possibility of a propagating zirconium-water reaction, which could evolve significant heat and potentially release and disperse fission products.

But action is being taken to avoid such an eventuality, at least as far as I can tell.

well, apparently Tepco has admitted they think the RPV in reactor #1 was damaged due to overheating and meltdown. They state that seals and other parts may have leaked due to the extreme temperatures. I believe that they previously thought that the RPV was damaged and created holes that were leaking but now its all about the temperatures that exceeded the design of the RPV and how that caused seals to leak. This was apparently T+18 hours from the quake.

Tepco appaprently also has admitted that the ECCS for reactor #1 operated correctly after the quake but was then turned off for about three hours because of low temperature readings. It was turned back on 3 hours later. I wonder: faulty instrumentation may have misled the operators into thinking they did not need the ECCS on? distractions due to the tsunami? three hours later they got better instrumentation and turned it back on once they realized their mistake?

is three hours sufficient time to cause the reactor to heat sufficiently that cooling no matter what would be too little too late?

“The simple fact you can’t argue about either, is that nuclear and hydro are the safest forms of energy generation.”

I understand completely your rationale for writing this, but from the perspective of a member of the Japanese public I very much doubt they would agree with this.

Consider this thought process from a Japanese resident:
1) Three nuclear plants exploded after an earthquake.
2) I was repeatedly told that they were designed to withstand earthquakes
3) ca 100,000 people have been evacuated; contamination levels and ongoing risk of further incidents mean there is no timeline for their return.
4) I trust the nuclear industry and nuclear power is safe

Same problem here as with climate change — another case where computer modeling and inference from observations are available; but direct observations aren’t available and won’t be until it’s too late to deal with the causes of the problem.

“May 25 (Bloomberg) — Tokyo Electric Power Co. said the containment chambers of damaged reactors at its Fukushima nuclear plant were likely breached, identifying additional source of radiation leaks that may exceed Chernobyl.

Computer simulations of the meltdowns of three reactors in March indicates holes formed in chambers, the company known as Tepco said in a report.

‘Unfortunately I can’t find any consistency in the report,’ Hironobu Unesaki, a nuclear engineering professor at Kyoto University, said by phone. ‘Tepco hasn’t released sufficient radionuclide analysis of leaked contaminated water. Now they’ve confirmed fuel rods melted, they should also release more data including plutonium and uranium readings….'”

“The fault that generated the Tohoku-Oki earthquake … report in the latest issue of the journal Science Express…. it ruptured in a “flip-flop” fashion — first breaking westward, then eastward.

… The second motion — generating magnitude-6.5 aftershocks — deformed the seafloor with such force that a huge tsunami was triggered.

… the two-faced rupture made the devastation greater than it might have been otherwise ….

“… what we need to figure out is whether similar earthquakes — and large tsunamis — could happen in other subduction zones around the world,” Beroza said.

The project was a collaborative effort. Stanford’s Beroza and graduate student Annemarie Baltay measured the energy released by the quake, while University of Tokyo’s Satoshi Ide modeled the slippage of the fault.

‘This amplification of slip near the surface was predicted in computer simulations of earthquake rupture, but this is the first time we have clearly seen it occur in a real earthquake.'”

What do we know? What are facts? How does that comport, or contradict our previously held judgments.

US type designs, light water reactors, were based on a once in 10,000 year recurrence event, a core melt down with biblical (my term) consequences, . In fifty years, we now have suffered four melt downs. But not one person has died of radiation. The long term death from accidental release of radioactive isotopes, public health predictions, range from near zero, per pro nuke types, to millions per anti nuke types. (Climate change has similar scientific differences of expert judgment.) Fukushima was hit by an earthquake five to ten times larger than its design basis (depends on varying media reports). It almost made it. It was hit by a tsunami, over twice its design basis. And drowned the emergency generators placed in the basement. It took over two weeks to restore power, melt downs took hours. TEPCO lacks basic plant instrumentation data. The loops either do not exist, or were destroyed en mass. There are enormous gaps in our knowledge of what happened.

US nukes once were put on line for $200/ kwe; the planned facilities project circa $10,000/ kwe but one, in Texas, doubled in a few months, and was cancelled. We have no current track record.

I designed a score, that work, in the range of $800 – $1600/kwe. The last big one took over a decade to go on line. Current Chinese experience is more than twice as fast. (interest on construction loans is a huge cost consideration of any multi billion dollar investment.) I know the NRC does not know what it is doing. They were forbidden by law to consider costs, and by culture to be anti business bureaucrats. The Commissioners are political appointees, and reflect deep partisan conflicts. They are highly trained academics, or lawyers, with no real world experience. Billions are wasted, real problems are ignored. I had intense interaction when things were built, I am ignorant of what they have done in almost two generations.

Reviewing the cards, I judge Fukushima to be really dangerous (to Japan, not the US), in a meta-stable condition. The policy of storing generations of spent fuel in pools, because politics has frozen back end technologies, is a latent suicidal decision path. Spent fuel must go somewhere safe, contained in dry sealed containers, and located deep underground in one, seismically stable, heavy guarded government facility, and/or reprocessed. (This established policy is vehemently fought by the current Chairman of the NRC who worked for anti nuke factions in the US Senate/House.) IMHO, he is violating both the spirit and letter of the law defining radioactive waste management signed by President Reagan in Jan. 1881. His orders are being litigated.

Fukushima must force fundamental societal risk reassessment. The issues are technically related, but are essentially ideological in nature, i.e which authority do you trust? Citizens have been told, no problem, and, you are going to die horribly, by experts. This must stop, on both sides of the Pacific.

Again as long as people who claim to be experts use the words “biblical” and “suicidal decision paths” to things that have the lowest impact of any energy generating technology, we will not advance our cause. I’m sorry to say this Hails but you’re being an extreme hypocrite, first talking about how some decades old fuel rods that sit in a concrete packadge is suicide, without presenting any plausible scenario why this would be so, and then, well then, you say experts say we are going to die has to stop.

Seriously dude.

It occurs to me that we just won’t solve the CO2 problem. We’re much more interested in theoretical debates than actually looking at reality. We’re not interested at all in comparing apples to apples and chosing the least horrible solutions.

The future is fossil – just as it is in the present. Buckle up. It may be a rough ride.

Fukushima must force fundamental societal risk reassessment. The issues are technically related, but are essentially ideological in nature, i.e which authority do you trust? Citizens have been told, no problem, and, you are going to die horribly, by experts. This must stop, on both sides of the Pacific.

Hear, hear!

The problem, of course, is getting everyone on the same page. Nuclear energy is beset by enemies from parts of the political and business sectors, and by opportunistic parasites that feed on fear. Putting an end to this, given how deeply it has become entrenched, will be a very difficult task.

“On Sunday, Tokyo Electric Power Company began measuring the density of radioactive elements above the No.1 and No.4 reactors.

The firm used instruments attached to the crane pumps that are injecting water into the reactors.

TEPCO detected 360 becquerels of cesium-134 per cubic meter above the No.1 reactor, where most of the fuel rods are believed to have melted. The amount is 18 times the allowable limit for the plant’s perimeter.

The firm also discovered 7.5 times the limit of cesium-134 above the No.4 reactor, which has no fuel in its core. The substance is believed to have come from the fuel storage pool and the neighboring No.3 reactor.

TEPCO says it will measure the levels of radioactive elements above the No.2 and No.3 reactors. It also plans to cover the reactor buildings with polyester sheets to prevent the further dispersal of radioactive materials into the air.

> Uranium and Plutonium measurements for
> the basements
Thanks Harry; have you seen any trend-over-time charts lately? I recall charts a month ago; haven’t seen one lately.

The “Plant Status Fukushima Daichi” handout dated May 25th (handouts_110525_02_3.pdf) says they’re working on analyzing samples from spent fuel pools; no mention of further samples from groundwater or basement under the reactors.

“- We are conducting detailed nuclide analyses on the water collected on April 12 from the spent fuel pool of Unit 4.
– We are conducting detailed nuclide analyses on the water collected on April 16 from the skimmer surge tank of Unit 2.
– We are conducting detailed nuclide analyses on the water collected on May 8 from the spent fuel pool of Unit 3.”

“Detected density of Pu-238, 239 and 240 are the same level as that of the measured fallouts
in Japan in the cases of previous nuclear tests in the atmosphere. However, this can be considered to be caused by the nuclear accident of this time….”

Help interpreting this, does anyone know?

Does this mean the release of plutonium detected near the plants now is about the same amount that was measured some years ago from the Chinese nuclear tests?

Or are they saying the current accident released an amount comparable to what remains _now_ from the Chinese bomb tests?

“The activity concentrations of I-131, Cs-134 and Cs-137 in seawater close to the Fukushima Daiichi plant at the screen of Unit 2 have been measured every day since 2 April. … There was a significant increase in levels of I-131 from about 8 to 80 kBq/L from 10 to 11 May, in parallel with the increase for both radiocaesium isotopes. This indicates that there is still some production of fission products. The I-131 levels decreased to about 20 kBq/L on 17 May.”

I wonder — anyone seen speculation or measurements on how long it takes for water from inside the pressure vessel to leak down to the seawater detection site? That would help guesstimate how long ago that iodine-131 was created (and so how much decayed away before it was measured in the ocean).

I wonder if they’re sampling water from underneath the pressure vessel as it leaks out, as well as when it gets down to the ocean. That would be much closer to realtime tracking what’s going on in there.

PS — warning — just because a press release says “significantly” doesn’t mean they did the statistics on a trend, though it would be very helpful to know more about the numbers.

Barry, have you covered statistics and trend detection here? I looked briefly and didn’t find it.

Detection of _very_small_ changes can be “significant” in the statistical sense — useful to try to track what’s happening inside the reactors — while not being “significant” in the sense of surprising or unexpected.

It’d be no surprise if, in a mess in the bottom of the containment, stuff is getting stirred around by the flow of water, that would let bits of fuel occasionally get close enough to produce some new short-lived fission products — that’s what tracking I-131 should help decide. I think.

Deciphering the measured ratios of Iodine-131 to Cesium-137 at the Fukushima reactors
T. Matsui
(Submitted on 2 May 2011)

We calculate the relative abundance of the radioactive isotopes Iodine-131 and Cesium-137 produced by nuclear fission in reactors and compare it with data taken at the troubled Fukushima Dai-ichi nuclear power plant. The ratio of radioactivities of these two isotopes can be used to obtain information about when the nuclear reactions terminated.

“…. the data from water samples taken from four sub-drains near the reactor buildings show even more puzzling features, as shown in fig. 2.[14] In particular, the water samples from the sub-drain near the unit-2 reactor building show an anomalously high radioactivity ratio.[15], even greater than the upper bound given by (11) if the nuclear fission ends on X-day as indicated by the red solid line in the figure. If there is no strong chemical filtering effect in draining contaminated water from the reactor buildings, it would be difficult to understand the observed anomaly near the unit-2 reactor without assuming that a significant amount of fission products were produced at least 10 – 15 days after X-day.
The data from the unit-3 sub-drain before April 23 sit close to the decay line which fits to the sea water data, hence they may be understood as due to radiation from fission products produced before the X-day. However, the data of the unit-1 sub-drain and unit-4 sub-drain give high radioactivity ratio, even larger than that of the samples from the unit-4 cooling pool and from the unit-3 sub-drain. The data therefore cannot be explained by the contamination of the old fission products which had existed in the spent-fuel rods in the unit-4 cooling pool. The new data of April 25, however, show very different characteristics which are difficult to be understood unless there was considerable mixing of waters belonging to different sub- drains due to in-flow and out-flow of water through underground water channels.
In conclusion, the ratio of the measured radioactivity of I-131 and Cs-137 may be used to extract useful information about when these fission products were produced in the nuclear reactor complex of the Fukushima Dai-ichi plant….”

On slide 7 is a scenario of 1.81 MBq/m2 of Cs137 (as indicator for other FPs including 70 MBq/m2 of iodine isotopes), on slide 23 is a dose of ~8 uSv/h from ground radiation.

This weak association suggests that the 3 MBq/m2 edge of the red coloured (plume running 35 km NW of Fuku. NPP) area would give a dose of 13 uSv/h. Temporarily, that rate would exceed 100 mSv/a, before reduction by die-away, rain and bioturbation.

Not enough to give me any symptoms, but the iodine might be a threat to children.

Hank, as I read the soil plutonium detection notes, they mean they can’t tell whether the detected material was bomb-test-era or not. If it’s not, it’s in such tiny quantities that it almost could be (so really not a big escape of any sort) and it hasn’t changed since they started collecting (so no continuing build-up). The sampling for uranium and plutonium in the turbine basement water all came back completely negative (<x typically meaning below detection limit), so that could be a conclusive "no" depending on water connectedness.

it's possible that occasionally the loose fuel would get into a configuration for fission, but the figures from IAEA – despite their conclusions – don't really seem to be conclusive on their own. Certainly the decreases are not all attributable to half-life decay effects, and the increases may be nothing more than another more-contaminated pool finding its way to the sensing area.

I'm almost certain "significantly" is not used in any statistical sense. Note that a "configuration for fission" does not necessarily mean closer together; moderator is required between neutron and next fissile target.

Just saw your next post (8:54AM) Hank… great paper, ratios of elements are fascinating; ratios of isotopes of the same element are even better, because they will behave compatibly in a chemical & physical sense also. As your reference bears out strongly, the picture is extremely confusing, and there is no clear winning explanation.

“… Plutonium isotopic ratios in the deposition samples suggest that significant amounts of the recent 239,240Pu deposition observed in Japan are attributed to the resuspension of plutonium-bearing surface soil particles; resuspended plutonium originates from the East Asian arid areas. The recent increased tendency of 239,240Pu content in residues in deposition samples may reflect desertification in the East Asian continent.”

“The large amount of carbon dioxide (CO2) emissions and the fast development of nuclear power plants in China pose challenges for the safe disposal of CO2 and high-level waste (HLW). Significant progress has been made in both areas. … Seventy disposal sites in 24 major sedimentary basins have been identified for CO2 disposal. The amount of spent fuel will reach about 82,000 t of heavy metal when all of the planned 58 reactors on the Chinese mainland reach the end of their lifetime. A target to build a national HLW repository in around 2050 has been set. CO2 disposal and radioactive waste disposal have much in common ….”

“Nuclear energy is beset by enemies from parts of the political and business sectors, and by opportunistic parasites that feed on fear. ”

Yes, and it’s also beset by having overpromised on it’s cost and safety benefits, and refusing to openly address these.

In the ca 50 year history of civil nuclear power there have now been five significant meltdowns (TMI, Chernobyl, Fukushimax3). The latest has caused the evacuation of significant populated land areas for what is currently an indeterminate time. If the wind direction had been different it could well have been far worse.

If I wanted nuclear power to have a future I would be arguing for a wide ranging enquiry, supported internationally, into the technical, human and political causes of these safety failures so they can be addressed in order to help humanity fight climate change.

Given the very obvious failure of nuclear safety at Fukushima, I would not be calling those who oppose nuclear power “parasites”. Humility, not aggression is called for and would do your case much good.

@Brian – As usual a total lack of perspective on the relative dangers between modes of generation are glaringly obvious here.,as is the tendency to overstate the magnitude, and the impact of these incidents.

Holding nuclear energy to a far higher standard then any other comparable technology, and accepting the overreaction of the authorities only indicates to me that you don’t really understand what is going on and have chosen to buy into the very propaganda that I was writing about.

This is the crux of the matter: broad acceptance of a narrative that is being managed by those that do not want to see nuclear energy grow. Those of us that have chosen to drill down deeper have found that deaths caused by coal, failures of hydro dams, and natural gas explosions, have taken many, many more lives than nuclear over any given period. This doesn’t even take into account the broad damage being done to the environment by these modes.

How many people do you think have been displaced by the creation of hydro reservoirs? Have you ever bothered to check? Yet you give more weight to those displaced by a natural disaster, than those displaced by their own governments in the name of ‘the greater good.’

Wakeup and smell the coffee – you are being led around by your nose for someone else’s agenda. Or at least stop defending them.

Those of us that have chosen to drill down deeper have found that deaths caused by coal, failures of hydro dams, and natural gas explosions, have taken many, many more lives than nuclear over any given period.

I am, indeed, amongst those who have dug deeper and I have “bothered to check”. I fully understand the issue of overall deaths and absolutely agree that on that basis, nuclear is safer.

Also, on climate change, I think it’s almost inconceivable that without a significant increase in nuclear generation we will prevent catastrophic effects over a timescale of decades or centuries.

The point I am trying to make is that, this will not happen unless the very obvious failures of nuclear safety evidenced by Fukushima are properly and openly addressed.

Presented with images of exploding nuclear plants and extensive contamination requiring long term evacuation zones you will not gain support for nuclear investment without genuine change in how nuclear safety is managed.

You need to realise that to the public, five meltdowns in fifty years is not an acceptable safety record given these consequences. It is irrelevant whether people understand the more insidious effects of fossil fuels or not – the effects of nuclear failure are very, very obvious. Nuclear safety needs to improve, not because nuclear has a bad overall safety record, but to demonstrate that it can be good.

I was brought up within sight of a nuclear power station, I’m a trained engineer and I’m comfortable that the risk can be managed. But I can fully understand why, given Fukushima and Chernobyl, the public aren’t, and I do not accept that the design and operation of Fukushima was adequate.

Wake up and smell the coffee – to any ordinary member of the public, Fukushima shows that the nuclear industry cannot be trusted be safe.

Your desire to change that is doomed to failure by an aggressive response to challenge.

I’ve only just opend this thread and I haven’t read all the earlier posts, so forgive my lack of background.

My opinion on the issue you are talking about is different from most BNC regulars and very different from yours.

My position is that nuclear must be allowed to be cheaper than coal if it is going to cut world emissions significantly. 80% of the growth in world emissions between now and 2050 will come from the developing and under-developed countries. These countries will bur the least cost electricity technologies, If coal is cheaper than nuclear, they’ll buy coal.

It will not achieve what we want if we ramp up the cost of nuclear even further than it is now. In fact, we need to reduce the cost of nuclear considerably.

Nuclear is over regulated. The excessive regulation is not providing greater safety but is greatly raising the cost http://www.phyast.pitt.edu/~blc/book/chapter9.html . What will provide improved performance, efficiency and safety and lower the cost is to wind back the restrictions and let it go through the normal development cycle that technologies go through. DV82XL often points to the progression the aerospace industry went through and how safety improved as a result. We need to allow nuclear to go through the same development cycle. We can do that best by removing the excessive regulation and shackles. Luckily, China, Korea and Russia are doing that without any help from the West.

In my opinion reducing cost of nuclear should be our prime objective. Nuclear is already plenty safe enough and it will get safer as it develops. I understand the politics you are arguing about, but the issue of rolling out nuclear is not primarily an issue for the western democracies. The real issue is about giving it a cost advantage over coal and making it suitable for roll out to the developing world.

All this IMHO, of course. Now, having stirred the pot, I can sit back and watch the tirade :)

Brian, I agree with you totally. I am a long time supporter of nuclear, but the outcome of Fukushima is not good. The contamination plume to the northeast is a big problem for Japan and the industry. The preaching to the converted mentality is counter productive and a big turn off to the average person in the street. The industry and government need to show humility and resolve.

Rick, on 26 May 2011 at 10:19 PM said: I am a long time supporter of nuclear, but the outcome of Fukushima is not good.

I think the outcome of Fukushima will eventually be that there is ‘life after a nuclear accident’.

The only explanation I’ve ever come up with as to why anti-nuclear sentiment is comparatively low in the US Southeast and comparatively high in the US Northeast is that the Northeast doesn’t suffer devastating Hurricanes.

If one lives in the US Southeast then every few years a big hurricane is going to come along and do enormous damage. The residents evacuate or weather the storm, then return and rebuild just as a matter of ‘normal life’.

In nuclear accidents, Hollywood and anti-nuclear advocates have sold a version of events that life wouldn’t go on, and if you were unlucky enough to survive you would eventually suffer a painful, lingering death.

The bulk of the ‘painful lingering deaths’ as a result of Chernobyl were from people who took up excessive alcohol consumption because they were convinced they would die a painful lingering death.

@Brian & Rick – The public only learns to live with risk when they have been inured to it. That is why the majority doesn’t think about the risks of hydro dams, or thinks too much about the land destroyed by coal mining. Its the reason people get in cars and aircraft, not because these things are intrinsically safe, but because they have become indifferent.

Things won’t get worse in the long run for nuclear because of Fukushima, it will in fact get better, simply because that’s how humans react. The only thing is that going to happen is that antinuclear demagogues will use it as a short term platform, but in the end even that will pass.

And like G.R.L. Cowan, I don’t give any weight to remarks that start, “I am a long time supporter of nuclear, but …”

Bavaria is the state with the highest percentage of nuclear energy in Germany, but also has access to water power. (alps..)

at the same time the European Union countries without nuclear power are organising a front against the countries supporting nuclear.

—————–

“What will provide improved performance, efficiency and safety and lower the cost is to wind back the restrictions and let it go through the normal development cycle that technologies go through. DV82XL often points to the progression the aerospace industry went through and how safety improved as a result. We need to allow nuclear to go through the same development cycle. We can do that best by removing the excessive regulation and shackles. Luckily, China, Korea and Russia are doing that without any help from the West.”

—-

i was seriously surprised by this suggestion. Nuclear power is very different from the aerospace industry. basically accidents happen less often but have a much bigger effect. (turning big parts of a country inhabitable, at least for a significant amount of time).

more, but smaller accidents are a much better environment for a trial and error approach than rare and big events.

basically we can not afford to have any nuclear meltdown incidents at all.

ps: the source you linked above looks horrible. the chapter about Chernobyl doesn t make any sense any longer after Fukushima, an accident in western type reactors.
the lessons from Fukushima also obviously contradict the meltdown chapter of the book.

It says “The total cost of a power plant is defined as the total amount of money spent up to the time it goes into commercial operation.”

That’s not, nowadays, how the total cost is calculated.

But worse, look at the chain of logic he assumed back in 1990, leading up to arguing against the probable risk estimates published by the Union of Concerned Scientists:

“we calculate the LLE from reactor accidents according to the Nuclear Regulatory Commission Study which estimates one meltdown per 20,000 reactor-years of operation, and an average of 400 fatalities per meltdown.” (Chapter 8)

What are the current numbers? (We know “meltdown” isn’t well defined)

Events at Fukushima proved his, the governments’, and the industries’ assumptions wrong.

“… great care is taken in siting plants to avoid proximity to potentially active geological faults. (Widely circulated stories about plants being built on faults are not true).” (Chapter 6)

“… One type of LOCA in which the ECCS would not prevent a meltdown is a large crack in the bottom of the reactor vessel, since water injected by the ECCS would simply pour out through that crack. This would not occur with pipe breaks since all significant pipes enter the vessel near its top.” (Chapter 6)

(water drained by leaks from control rod seals )

Continuing from Chapter 6:

“… consideration of the several “precursors” to core damage that have already been experienced in reactor operation. By noting what further failures could have caused these incidents to escalate into core damage and estimating the probabilities for these further failures, one can arrive at an independent estimate of the probability for a core damage accident….”
….
The RSS estimates that a reactor meltdown may be expected about once every 20,000 years of reactor operation; that is , if there were 100 reactors, there would be a meltdown once in 200 years.7 The report by the principal organization opposed to nuclear power, Union of Concerned Scientists (UCS),21 estimates one meltdown for every 2,000 years of reactor operation ….

If the UCS estimate is correct, we should have expected three meltdowns by now ….” (Chapter 6)
________________________________

Please answer it yourself. How many fatalities? And please put your figure in perspective; i.e. fatalities per MWh of nuclear generation compared with fatalities per MWh of coal generated electricity – in both cases over the full life cycle. And averaged over a sussiciently long period such as 50 years. Refer to Figures 1 and 2 here, the accompanying test and the references for assistance:https://bravenewclimate.com/2010/07/04/what-is-risk/

Remember also that nuclear is getting safer all the time (Fujushima is 1950/60’s design), and will get safer faster if we reduce the costs so it can be rolled out faster.

basically we always learn this, when water is missing, which obviously is too late.

Greenpeace has taken samples and has found high levels of radiation in all sorts of seafood. has the japanese Government or Tepco provided any data on this so far?

————-

in related news, Tepco is now saying that it did inject sea water longer than they originally said.

“The firm said it had continued to inject seawater into one of the damaged reactors soon after the March 11 tsunami, reversing an earlier statement in which it said it had suspended the risky measure amid pressure from the prime minister’s office.”

cohen’s numbers are still considered correct for reactors like diablo canyon. Indian Point on the other hand was rated at one every 10 thousand reactor years and Fukushima? I don’t think Cohen would go along with giving that the “normal” gen two rating, given the siting and the clustering (given the siting).

At any rate, 3 reactor accidents do not prove cohen wrong. in fact, it wouldn’t prove him wrong even if F was legitimately rated at the gen two norm.

Chernobyl doesn’t count in Cohen’s calculus, btw, and as I said, neither should Fukushima. So it’s not three accidents, but two max, and not even that.

by the way, 400 or so reactors would change the accident ratio to once every 50 years. with ucs, that would be one accident every five years, Hank. so your implication that UCS is correct is incorrect.

the result show a majority of opponents in several countries now, including Japan. there also seems to be a majority for keeping nuclear power at the level it is today.

barry ran a post about prominent people switching their nuclear views after the accident. (and many of them towards a pro-nuclear view!) now it looks like some of these changes might have been affected by the feeling that the Fukushima reactors had been able to withstand the earthquake very well and the limited evacuation zone 8and no deaths) giving the impression that the effect of the accident might be small.

Now it is turning out that much of this information was false. people in japan for example are buying geiger counters in great numbers which does not suggest a strong believe in their governments information.

GRL Cowan and DV82XL. I repeat I am a long time supporter of nuclear power. Your somewhat personal and immature response is actually what I was referring to. The fact is there is about 800 km2 which will be an exclusion zone for many years. Green peace will have a field day with it. The reality is that anti nuclear sentiment has grown. You will not counter this by defensive and dismissive approaches. In public affairs perceptions are reality. Regulators must deal with this. In the west, the industry will take many years to recover. In the meantime we have to hope developing countries can pick up the baton.

The reactors at Fukushima were knowingly built in a seismic zone. They were designed accordingly. The design has proved inadequate and has resulted in a large area being evacuated for a significant time.

Some reasonable questions for the nuclear industry follow from this. For example, moving for specific to general:

1) Are there other reactors whose design is inadequate for known seismic hazards? If so, what should be their fate?

2) Are there other known and designed for hazards where the design of nuclear power stations is inadequate?

3) Are there hazards not designed for which in the light of learning from the impact of this incident, should be designed for?

4) Was learning from other incidents such as TMI implemented at Fukushima? If not, why not? How can we ensure this happens in future?

5) Have political imperatives undermined nuclear safety? Eg storage of spent fuel. Can the nuclear industry operate safely in this political climate and if not, how can it be changed?

This is an accident which should not have happened. To respond as you do by reasserting the safety of nuclear power, merely serves to reinforce the perception of a nuclear industry unable to build a culture which openly addresses genuine safety issues.

Leo: Your approach is statistical, whereas climate models simulate the physics. It’s chalk and cheese. You come up with a 0.32 degrees per W/m2 and the other Hansen comes up with 0.75 degrees per W/m2 using Paleoclimate data … without simulating any physics. Here’s the paper:http://pubs.giss.nasa.gov/abstracts/2008/Hansen_etal.html

If you want somebody to pick apart your method line by line, you could try posting to realclimate.org … they have more climate scientists on board who might be able to spare the time and have the expertise.

Both plants were struck by the monster earthquake and 14-meter tsunami. The Daiichi NPP suffered three (of six) damaged reactors whereas all of Daini’s four reactors are safely in cold shutdown. What is the difference? Newer, improved designs. Steve summarized:

The conclusion that one can draw from the events at the two Fukushima plants is relatively straight forward: While the older BWR-3 and BWR-4 designs are sufficiently safe in most situations, their designs are nowhere near as robust and reliable as newer reactor designs. Of course, despite holding up so well against forces far beyond what designers had planned, the BWR-5 is, by today’s standards, old technology. Newer reactors are much safer still and have even more reliable passive-based safety features.

This is all the more reason why we should be building more nuclear plants. As newer reactors are built we will be able to eventually shut down the older reactors, thus improving economics and safety even further. The events in Japan do not diminish the picture of safety we have when it comes to new reactors. Rather than assuming that reactors will fail in the manner that they did at Fukushima Daiichi, we should consider how well they held up at Fukushima Daini. This is far more representative of new reactor designs, although those are even safer and more reliable still.

thanks for this link. even though i disagree with several points being made (and the conclusion, of course), i found the article to be a very good reading and full of good information. exactly the kind of stuff that made me read BNC!

i think the article should take a closer look at the emergency Diesels, as these were one of the main problems. (placement of the diesels was more important than reactor type, i fear)

i think the Fukushima lesson is simple: Nuclear power plants shall not be located at places that might be flooded. i was seriously shocked when i read in the German report of the reactor security commission, that water level of the highest expected flood would turn several plants into islands and would reach up to 0.5 meters below the entrance doors of the plant closest to my home.

( i would also suggest building nuclear power plants with the earthquake resistance of the japanese plants everywhere and NOT to build any nuclear power plants at all in regions that have extreme earthquakes)

—————-

on a different topic, it looks like the 7 nuclear power plants in Germany that were shut down after Fukushima will not go back online again.

The antinuclear side has been dropping comments admonishing nuclear supporters to tamp down the rhetoric in many pronuclear forums, generally hiding behind the ‘I’m a supporter of nuclear but’ line. What they would like is nuclear to go back to constantly apologizing, and looking at its feet mumbling when arguing its point. They seem to be distressed that we are taking more proactive tactics, because we are not making it easy for them to leverage Fukushima Daiichi to attack the whole industry.

Well too bad for you. We tried the soft approach after Chernobyl and wound up going nowhere for twenty-five years, it doesn’t work. We need to get the truth out and make sure that we don’t let our opponents set the agenda.

The fact that they’re trying to get us to stop means we must be doing something right.

DV82XL, for the third time I am a long term supporter of nuclear. I started in uranium business 25 years ago and am still in it. I deal with public perception every day. After Chernobyl happened our rhetoric was that it was a Russian design and would never happen in the west. An arrogant response to Fukushima will not go down well. I believe the response of the British has been the best, measured but firm. It addressed peoples concerns but restated that there are no alternatives if you want to address climate change. Fukushima is a failure for the industry that can’t be repeated. The failure goes beyond TEPCO and Brian has touched on those issues. I believe IAEA has been a failure and needs to be revamped. I also believe we have learned a lot from the media coverage and debate about where the perception risks lie. It us clear the media and public are totally ignorant of radiation and scared out of their wits. Somehow we have lost this battle comprehensively since Chernobyl even though the research from Chernobyl suggests the fears are overstated.

@Rick – If we have lost this battle comprehensively since Chernobyl, then perhaps you can expound on why, prior to Fukushima we were beginning what was called The Nuclear Renaissance, or why only ten minutes were allocated for leaders of the G8 countries to discuss nuclear energy at the summit in Deauville, France. There Nicolas Sarkozy summarized the discussion saying: “Many among the G8 think that there is no alternative to nuclear power.”

In another thread I wrote that the mood in Ontario, Canada is shifting with voters willing to embrace more nuclear builds, and the dumping of feed in tariffs for wind and solar. Perhaps you can reconcile this shift in attitude with your observations of public perception that you claim to deal with every day.

1. The updated BWR designs at Daini were surely important but I don’t think decisive in the relative outcomes of the two NPP. It isn’t clear to me how the two sets of reactors handled the seismic accelerations — perhaps Daiichi suffered greater damage in critical components.

2. It is clear that the tsunami impact was significantly different. I don’t understand exactly why, but Daini experienced 14M only on the south side of unit 1 but overall the site was subjected to a 7M inundation. Secondly the flooding depths were less at Daini being sited 13 meters above sea level (O.P.) vs Daiichi 10 meters above sea level (O.P.)

3. The bottom line is that Daini retained enough electrical power to operate reactor cooling: one (of four) off-site power lines survived, and 3 of 12 backup diesel generators. We don’t know how Daiichi would have fared if the same power supply had survived there.

( I would also suggest building nuclear power plants with the earthquake resistance of the japanese plants everywhere and NOT to build any nuclear power plants at all in regions that have extreme earthquakes)

I can’t agree with that approach, Sod. Empirical copycat design is not design at all. Structures such as NPP’s must be designed to suit the site, including earthquake risks as appropriate to that site. By all means, make the design robust, but to adopt a design standard that is appropriate only to a site on the other side of the globe is reckless and futile.

These things are all based on risk assessments, these days. What is the risk of each type of event? That should determine the response to the risk. High vertical accelerations? Horizontal accelerations? Flooding? etc – manage the risks for a safe outcome.

This thread has been taken over by pro and con arguments for AGW/CC. This is not the place to discuss these topics. This is an OT for Fukushima not a general OT. In any case these opinions belong in the Sceptics section. All comments such as these have been deleted from this thread. We do not have the facility to re-post your comments so you will need to do this yourselves and continue the conversation in the right section of the blog.

If I want to post about AGW, I have to post on the “How to recognize that people who don’t agree 100% with BB on AGW, are skeptics, deniers and fools OT”

Therefore you dont exist and are banished, never to be heard of again..MODERATOR
The thread is named “Fukushima Daiichi Open and Update Thread #6” – there have been 5 previous such threads.
The general Open Threads are up to number 15. If you wish to post any AGW/CC remarks on the general OT 15 you are at liberty to do so, however the “Sceptics” category includes posts by Barry such as “What if the sun got stuck? (Posted on 14 September 2008)” and “More ice, flat temperatures – what does it all mean? (Posted on 27 April 2009)” so this is where the responses to such arguments will most likely be read and where answering comments will appear.
Much of the discussion re AGW/CC that was going on in the Fukushima OT #6 by you and others, has already been debated in the relevant threads. It is BNC policy that off-topic comments, especially when they generate multiple replies and begin to clog the thread, be deleted and asked for a re-post in the correct thread. That goes for any off topic comments and not just AGW/CC. You are not being singled out for special, unusual treatment.

@Leo Hansen – Rubbish. Even as the Cold War was sending kids like me cowering under our desks during nuclear attack drills, we were having the benefits of peaceful nuclear energy extolled to us by just about every form of media. The Atomic Age was everywhere from home design to product names and we believed we were on the cusp of a brave new future.

Antinuclear energy sentiments came much later, when the Ban-the Bomb movements started looking for something else to justify their existence after the START process got under way.

Why not *read* what I’ve written up the thread. (deleted inflammatory remark)

Direct quote from my response to one of your earlier:

“I think it’s almost inconceivable that without a significant increase in nuclear generation we will prevent catastrophic effects over a timescale of decades or centuries.

The point I am trying to make is that, this will not happen unless the very obvious failures of nuclear safety evidenced by Fukushima are properly and openly addressed.”

Hank – thanks for the link to inquiry. Personally I think something much wider than a narrow technical investigation is necessary, with international buy in if we are to retain nuclear as an option. Any chance or sign of that materialising?

The point I am trying to make is that, this [nuclear growth] will not happen unless the very obvious failures of nuclear safety evidenced by Fukushima are properly and openly addressed.

You do understand that the event at Fukushima was not a systemic failure inherent to nuclear energy, but that of a plant operator not having the necessary backups in place to deal with this emergency.

In fact one can conceive of similar incidents happening at, say a chemical plant, where a failure of a backup system, due to operator shortsightedness would cause a large scale event that released poisons, and required large scale evacuations.

The difference there is that there would be no calls from antichemical zealots calling for the closure of all CPI facilities or assertions that the event proved that this industry as a whole was unsafe, and should not be permitted to grow.

MOST nuclear plants operate safely, and as after TMI, Chernobyl, this event had national regulators crawling over the reactors in their bailiwicks, to cover their behinds. Notably there were no major findings suggesting that the world’s reactor fleet was unsafe.

You, and those like you are making a tempest in a teapot, and if as you claim, you are a friend of nuclear energy, then it needs no enemies.

Someone explain to me why such systems were not installed in the emergency steam vent lines. There could have been a factor of 50000 less cesium and iodine with some simple activated carbon beds.

Anyway, installing those systems on the emergency steam vent lines is a simple and cheap alteration. Using 1 month of submarine (used by scuba divers) grade lithium batteries to power the valves and control room is also cheap (less than a million for a large reactor). A diesel generator on the top floor with direct DC connection to the cooling pumps would be nice also.

Just make the changes and keep the plants running. We can’t have them replaced by dangerous deadly coal and natural gas plants (or renewable energy that would otherwise have replaced other dangerous deadly coal and natural gas plants). Meanwhile we need 10 TWe of new reactors. These have sufficient passive and redundant features but should also be reviewed in light of the lessons of Fukushima.

The Nuclear Power debate is played out on the emotional battleground of FEAR not rational and logical thinking. You’re rational so you can’t accept that. People are first and foremost innate emotional creatures, but rational logical thought is a learned process.

Maybe I am wrong but I think people are fearful because there always seems to be a lack of transparency and a feeling that the only people involved in this fiasco are the industry itself and the interested political players. Even IAEA seems to be part of the industry so how are we going to trust there assessment. They are unlikely to conclude that nuclear power is to risky. lol . I just wish there was an organisation with true independents at the heart of all this.

I suppose I look back at the collusion between the tobacco industry and governments (same with oil) to see that we get lied to and information is dumbed down to stop us mere mortals from having to much knowledge.

I am not sure if I am typical, however there is very little in the UK concerning opposition to nuclear, yet people I speak to have suspicions.

Cyril says: Its very easy to prevent Fukushimas with some simple enhancements.

And goes on to describe activated carbon filters.

Cyril, you shouldn’t wonder why people don’t take nuclear advocates such as yourself seriously if you say things like this.

I completely agree that radiological releases caused by venting steam to reduce pressure in reactors could be virtually eliminated by this sort of technology. To describe the problems these reactors have had as fixable with this sort of technology is simply ludicrous.

If you’re not sure why that is, think: earthquake damage to cooling system, molten fuel rods, hundreds of thousands of tons of radioactive water, hydrogen explosions, and on and on. The situation may or may not get substantially worse: hopefully the worst is over, the corium can be contained and cooled, and the decades long cleanup process can begin.

The rest of your suggestions are similarly optimistic. Having the control room powered up is great – if it’s not too radioactive to work in. Having electrical power for the valves is great – if the piping is sufficiently intact AND the entire cooling system is operational. Turning the valves on doesn’t help much if cooling water can’t be pumped in.

Your suggestions are a step in the right direction for sure, but to say a powered control room and an AC filter would have prevented problems at Fukushima is beyond the pale.

Beyond the pale, nonsense; the ONLY problem for public health at Fukushima is the release of iodine and cesium that settled when the fallout came down. The iodine is now gone. The cesium is still there and is causing evacuation issues (not that I actually buy the external gamma dose risk from cesium, considering the Taiwanese cobalt-60 experience, but its a concern to the public and regulators).

The hydrogen explosions would be AVOIDED by having the vent line terminate to a hardened chimney ABOVE the reactor building. The hydrogen might still have exploded above that line, which would be spectacular, but not dangerous to the public, as it wouldn’t cause building damage.

For sure we don’t want reactors to melt down. But if you prevent major radionuclide release to the environment, by using simple passive equipment, then its not a public safety concern. For sure it costs money to build a water treatment facility and clean up the reactor site plus decommission the mess, but this is purely a financial issue, not public safety related.

I’ve suggested some other simple cheap improvements that must be made to older reactors if they don’t have them already. For instance a submarine grade lithium battery to power critical valves and instruments for a month or so (only a few kilowatts needed), extra diesel generators with direct DC connection at the top of the building, and passive hydrogen recombiners in the containment to prevent excessive hydrogen buildup. We’re talking about maybe 5 or 6 technical additions/changes, and yes this would clearly have prevented all damage to the reactor in the first place. Just make the changes and run the plants again. Replacing nuclear capacity with fossil is going to kill a lot of people prematurely and will pollute massively as well as adding more greenhouse gasses.

Plubmlechook – near the intake, yes. No one of the public is swimming there. My perspective is public health. Which means the people outside the plant area. There are no dangerous levels of iodine activity beyond the plant borders. You can see in the seawater measurements that there are no dangerous levels of activity in the seawater at all because it mixes with a huge body of water:

The time plan was at least ambitious and it has been obvious for quite some time that Tepco would not be able to stick to it.

today Tepco had to report that two workers have been exposed to higher doses of radiation.

—
“TEPCO said a test conducted at an institute last Monday found 9,760 becquerels and 7,690 becquerels of radioactive iodine-131 in the workers’ thyroids. This means they are likely suffering from internal radiation exposure ”
—

In a month’s time, they will be about 6% of the current figures, ie about 1kbq. What then? headlines from Sod, saying that these fellows have much lower than average I-131 in their thyroids?

Cyril’s point is a good one; you and the headline writer have hit the panic button a bit too early.

In Australia, we call it “Going off half-cocked.” I’ll let you find your own translation. It has something to do with the desirability of maintaining perspective and balance until you are sure of your facts.

Remember, newspapers are not written by medical experts or scientists or nuclear engineers or workplace hygeinists: their stories are selected to sell papers and the headlines are written to maximise the sales. Truth and balance and perspective and harmony and cooperation and honour do not sell newspapers. Drama does, even when confected.

In conclusion, it is reassuring that the careful examination of over 34,000 patients who received substantial radiation doses to their thyroid glands from 131I did not reveal a radiation-related risk of thyroid cancer.

And look at the internal dose due to naturally occurring radioisotopes which we’re all made of, you will see that the human body gets 0.3 or 0.4 millisieverts from roughly 8000 becquerels of activity in your body. This is similar to the thyroid iodine measurements in the highest worker exposures Sod mentions.

So if you find a roughly similar amount of activity in radioiodine in the thyroid, you will expect a similar whole body dose increment. That is to say, in the ballpark of 0.5 millisieverts. Now when we consider radioiodine’s beta decay tendency, this does mean the local dose (to the thyroid itself) will be much higher. So a question for the radiation experts – will the local dose be higher than 250 millisievert? Based on the small weight of the thyroid, it may well be, in which case Sod is actually correct.

“-TEPCO does not at this time believe that the rain and wind from the approaching tropical storm will cause any severe problems at the site. TEPCO had sandbagged a number of electrical distribution panels, and has taken other measures to ensure continuity of AC power during the heavy weather.”

Actually I don’t understand the “excess dose” story at all. At the specified I-131 dose, they would be nowhere near the limit.

Based on the weight of a thyroid gland at 60g, the decay energy of I-131 of 1.55×10^-13J and halflife of 8 days, the total acccumulated dose of 10kBq of I-131 should be less than 25mSv – probably significantly less, because most gammas will not interact with nearby tissue. I expect medical radiologists have a formula for that…

In any case, medical doses seem to be in the many MBq range, so 10kBq is basically nothing.

Shamus, I don’t want concurring opinions, I want people to come up with alternatives. Your links show that nuclear, including military nuclear power and research reactors, has killed thousands if not hundreds of thousands times less people than fossil fuels. A wind/solar+fossil backup grid is far more deadly than a nuclear grid simply because the nuclear grid requires much less fossil backup than the wind solar grid. Fossil fuels are the big killer. This is before considering greenhouse gasses at all.

Come up with a plan that adds up. Wind and solar don’t add up, unless you add a big fossil component. Which kills and pollutes.

Nuclear doesn’t have to be perfect, it just has to be better than everything else – which it has already proven to be.

That said, I believe that some technical additions must be made to older reactors, which we have discussed here and on other threads. Then we can keep these running and keep saving lives from fossil fuel deaths.

Anyway, just saying… depicting 50 years of nuclear safety by saying there’s only been 5 meltdowns is not the whole story.

The current US NRC event notification report sequence is 46,723. The sequence was 35,207 on December 31st,1998. So 11,516 ‘radiation safety’ related events in 12 years. 1,000 incidents per year in the US alone. The reports include things like malfunctioning x-ray machines , broken road density gauges , missing/damaged tritium exit signs. oncologists ‘missing the mark’ on radiation treatments as well as things that go wrong at nuclear power plants.

(Comment deleted for violation of the citation rule.Please read the rules on the About page and re-submit with your refs/links so others on the blog may read and fully assess the information and not rely on possibly biased or cherry-picked comments.)

“You do understand that the event at Fukushima was not a systemic failure inherent to nuclear energy, but that of a plant operator not having the necessary backups in place to deal with this emergency”

I think this is where we perhaps disagree. I think the accident has indeed uncovered systemic failures. Asking why the necessary backups were not in place would be a good place to start.

Such as:

1) The failure to adequately design for reasonably foreseeable events, and to heed prior warnings of this failure.

2) The failure to learn from incidents and improvements elsewhere.

3) The failure of the political system to allow for safe storage and disposal of waste, leading to the storage of large quantities of spent fuel adjacent to reactors.

4) The culture of the industry being to hide and reassure rather than openly address shortcomings.

Your reaction here merely serves to emphasise point (4). And to try and divide commentators here into pro and anti nuclear as your above posts do serves no useful purpose.

To deprive 100,000 people of their homes for an indefinite period is not a “tempest in a teapot”. The very fact that Fukushima opens up these questions is an opportunity to address them to give nuclear a credible future. To react by saying that it’s no big deal is to miss this opportunity and doom us to failure on climate change.

Brian, the fuel adjacent to the reactors is perfectly safe; it was the fresh spent fuel stored above the reactor building that is not safe. In my opinion, this is a design flaw – you don’t store spent fuel high up in the reactor building in a pool with only electricity based cooling capability. Storing spent fuel in a large below grade pool of water is perfectly safe, as Fukushima proved, and so is dry cask storage, which is also fine at Fukushima.

I do agree that the design basis events were too low for this location and this is a puzzle and a worry – why did regulators allow such a small tsunami as design basis? Why did the designers allow such a low level of tsunami protection? Why was there no electric generator attached to the steam driven turbine decay heat cooling system? Why were there no high class carbon filters on the emergency steam venting lines?

@Brian, Apparently you don’t know what the phrase ‘systemic flaw inherent to nuclear energy’ means, because you list particular flaw of the power station in question. Systemic flaws are things like the production of CO2 and ash from coal, or the intermittency of wind and solar. Nothing that happened at Fukushima falls in that class.

Thus it is a unique event that must be judged as a unique event, from which for a power station like Bruce Nuclear in Ontario, which is situated on the Canadian Shield, 3000km plus from the nearest open sea, has little to learn. Attempt to tar the whole industry with this event is dissemination at best, outright mendacity at worse.

Furthermore if we are to learn, or say anything about the evacuations, it should be to roundly criticize the government there for overreacting.

Come up with a plan that adds up. Wind and solar don’t add up, unless you add a big fossil component. Which kills and pollutes.
Nuclear doesn’t have to be perfect, it just has to be better than everything else – which it has already proven to be.

That really depends on who you ask. And five years from now, you yourself may flip on this, especially if solar continues to get cheaper, and most bet it will. Comment deleted – no ref to the article quoted – violation of the Comments Policy.)
My plan? Require every new corporation that builds anything to supply 5% of its own power from solar/wind/geo within the next five years. Require every new home built to do the same. Increase that percentage by 5% every 10 years or so. How many thousands of sq.miles of rooftops do we have in this world? Why not let’s cover them with solar cells?

@shamus, the limited uranium resources claim is an incredibly old and tired claim that misrepresents the known uranium deposits as all there is – not true of any mineral, let alone one as little explored for as uranium – and ignores other options, like the potential use of already-mined U-238 in advanced reactors or uranium extraction from seawater.

http://world-nuclear.org/info/inf75.html for more…MODERATOR
The unsubstantiated comment by Shamus was deleted for not providing references to support his claim – thank you for providing refs to support your.

You claim Fukushima was a “unique event” and ascribe it to “a plant operator not having the necessary backups in place”.

We need to ask *why* the necessary backups were not in place; *why* the regulators failed to spot it; *why* the operator chose to ignore warnings.

My answer is that the *system* of nuclear regulation failed. Any even in your terms there is a systemic failure of us to provide long term storage for high level waste.

Your analogy with chemical plants is good, and the Seveso II EU regulations show how specific learning from one incident can be well applied to correct systemic failure. Flixborough in the UK likewise brought about systemic change in the control of modifications.

Cyril R – by adjacent I meant immediately adjacent in the same building – I completely agree with your comments and you also highlight the systemic failures now evident.

Brain, I’m just not sure how useful it is to talk about ‘systemic failure’. I guess you can argue that external safety, in which I am involved on a professional level, is event-driven and only partially pro-active. You could argue that this type of external safety ‘attitude’ is a systemic failure. But how useful is this?

Much more useful is to make a list of things that went wrong in an accident, whether its a chemical plant or nuclear plant, and then use that to make a list of upgrades/technical changes required to prevent

What I find interesting at the Fukushima Daiichi events is that the upgrades required are obvious, simple, and low cost. So we can solve the issue of future nuclear safety during prolonged outages, large radiological releases, and flooding very easily.

I do agree about the systemic failure, but would stress that this is generic to the world of public (external) safety in general, and I argue that its much more useful to take a pragmatic, measures-based approach, rather than getting into philosophical debates of systemic versus technical failures. I talk to a lot of so called ‘environmentalists’ which get into these type of philosophical debates all the time, and its just not useful or productive.

Moderator: Here are some sources to the comment above that you removed. I fear now you have removed that comment, this comment is now going to be against the guidelines… but its an open thread… let’s see what happens.

If all the existing on Earth uranium beds are set in motion they can enable running of 440 nuclear power plants for 45-80 years. Uranium stocks will run out and all the plants and their infrastructure will turn out to be absolutely useless. Moreover, because of residual nuclear radiation these plants can’t be restructured for different functions.source

Perhaps the most worrying problem is the misconception that uranium is plentiful. The world’s nuclear plants today eat through some 65,000 tons of uranium each year. Of this, the mining industry supplies about 40,000 tons. The rest comes from secondary sources such as civilian and military stockpiles, reprocessed fuel and re-enriched uranium. “But without access to the military stocks, the civilian western uranium stocks will be exhausted by 2013, concludes Dittmar.source

Brian and V*2XL have differing views of the meaning of the term “systemic failure”.

Simply, DV82XL is correct, in that his interpretation corresponds with normal english usage.

See: Dictionary.com or Wikipedia, for instance.

Systemic refers to something that is spread throughout, system-wide, affecting a group or system such as a body, economy, market or society as a whole.

Brian may have drawn attention to failures at Fukishima, but he has not demonstrated that they are systemic by nature, beyond vague affirmations in his subsequent post.

No, Brian… Fukushima’s problems are plant-specific unless and until industry-wide spread is demonstrated.

We must use our best endeavours to ensure that our language is not debased by cliches and loose usage. After all, this is a web site, where 100% of our communication is via the written word. There are no facial expressions, no verbal inflections, no body signals. There are only words, which should be respected and treated with care.

@shamus, Apparently nether you or your sources understand how markets work. Uranium mines in known deposits are not being created BECAUSE cheaper uranium is available from military stockpiles. The reason is that this surplus has depressed the price, making it uneconomical to exploit other sources.

All other statements about a general shortage of uranium is wrong, and this has been established here on several other occasions.MODERATOR
Please supply a reference for your statement “Uranium mines in known deposits are not being created BECAUSE cheaper uranium is available from military stockpiles” otherwise it will be deleted.

“Should we take the most pessimistic prediction made by anybody and assume that? The consensus? The worst case to have happened anywhere in the world ever?”

it would be pretty easy to build new nuclear power plants high enough. simply place them 50+ Meters above the highest flood that pessimistic scenarios expect. (and do not build it below an overhanging cliff, to avoid the extreme scenario described in your “worst tsunami”-link)

the problem are the existing plants. their flood protection is often lousy, as described in the German report done after Fukushima.

the IAEA doesn t even mention damages done by the quake and calling the reaction “exemplary” is beyond bizarre.

after the accidents the plant was lacking such obvious needed goods as dosimeters or flash lights. they failed in bringing in back up diesels, water pumps or robots early enough. the workers had to go without beds, showers or fresh food until the start of this month. and even now there is danger of water leaking out, because they can not bring in water tanks in time.

so i am with Brian on this one: there is a systematic failure, basically the worst case was never considered. the plant was not prepared for response to a melt down and leaking radioactivity.

this is strange, because as Cyril said above, it would cost very little money.

Swiss is storing exactly this kind of emergency equipment now, so it is a systematic failure, that happened in several countries.

i also think that reports like the IAEA one are a systematic failure. the nuclear industry and society reacts in a defensive way, trying to downplay serious problems. in the long run, honesty and realistic assessments would be the better approach.

DV82XL : Hey if you say so. Don’t trouble yourself with citing any sources: if your unsupported contradiction is good enough for the moderator, that’s good enough for me. If you say the military sells uranium, it must be so. (snide remark deleted)MODERATOR
As DV82XL states:
“All other statements about a general shortage of uranium is wrong, and this has been established here on several other occasions.”
Facts that have been established on previous BNC posts cannot be expected to be continually raised and referenced for each new commenter. It is incumbent on you to research this site yourself. DV8 has been asked for the missing reference re the military.See also Moderator comment above. Note Shamus that DV8 has provided the ref above at 9:13 PM

The Megatons to Megawatts Program, the name given to the program that implemented the 1993 United States-Russia nonproliferation agreement to convert high-enriched uranium (HEU) taken from dismantled Russian nuclear weapons into low-enriched-uranium (LEU) for nuclear fuel has had a well known and classically predictable effect on the uranium market.

It can be argued that the long period of price depression followed by such a dramatic spike indicates that the uranium market is not functioning as it really should. The explanation for the way prices have behaved is ultimately quite simple. They were depressed for many years by abundant secondary supplies, which pushed them below the production costs of many mines, which then had to close.

@Sod – No one was ever arguing that this plant wasn’t unprepared for this event. I am arguing that this does not imply that ALL nuclear plants are unprepared, or in fact need to be prepared for this particular type of event as most are in seismically quiet zones, and/or far enough inland to be out of reach by a tsunami

The accident at the Fukushima-Daichii nuclear plant has generated worldwide news and precipitated public concern about the safety of nuclear power in general. The accident has already caused some governments to re-think their nuclear energy policies, notably including the Japanese and German governments. There have been calls for cancellation of nuclear construction projects and reassessments of plant license extensions. This may lead to a global slow-down of the nuclear enterprise, based on the perception that nuclear energy is not safe enough. However, the lessons to be drawn from the Fukushima accident are different.

My initial response is that, in parts, the language used appears to be somewhat of an apologia for NPP’s. This is unfortunate, because the underlying messages were about the need for calm and ongoing preparedness and the risks and costs of panic.

MIT are to be commended for their willingness to publish on this subject only a couple of months after the incident, while many matters are still incompletely investigated.

I think plant operator reactions were ok, with the important exception of waiting too long with the seawater injection.

I would blame GE for the design flaws of positioning the diesel generators and flood-vulnerable critical electronical infrastructure failing that is impossible to repair, spent fuel pools high up, not having a small electrical generator attached to the emergency steam turbine cooling system, not having high quality filter systems on the emergency steam venting lines, and letting the venting lines terminate to the upper portion of the building in stead of a hardened external chimney higher up.

TEPCO migh be blamed of being the most terrible communicator of the century. But it might be a bit early in the century for that ; )

I don’t blame the Japanese for not going with the frenzy that the US regulators had on their plants after three mile island. Yes some good improvements were made, but it was hugely excessive in most cases, and therefore needlessly expensive. If we look at the above design flaws it could probably be fixed for a couple million per reactor at most in new (mostly passively safe – no moving parts) equipment.

I would blame GE for the design flaws of positioning the diesel generators and flood-vulnerable critical electronical infrastructure failing that is impossible to repair

Not all the GE BWR’s have the electrical equipment in the basement.

I think that problem lays at the feet of Japanese regulators.

Venting inside provides time for the short lived radioactive material half lives to end.
In hindsight a foolish idea…the thought process at the time was probably to keep any radiation levels the public is exposed to as a result of any venting as close to zero as possible. “Penny wise, pound foolish” seems to apply.

It would have been less foolish if there were lots of passive hydrogen recombiners.

Personally I’d prefer just lots of carbon and HEPA filters in the vent lines. Remove 99.99% or so. And maybe even terminate the vent into an artificial lake next to the reactor so that any residual activity would be scrubbed and the steam would be quenched.

Sure you can also terminate the vent pipes into the sea, several meters below the surface, with sparger nozzles attached for maximum scrubbing efficiency. At least there wouldn’t be much air emissions to worry about (and the seawater emissions self-dilute to safe levels very quickly, contrary to some worried environmentalists). A seperate lake body would be even better though, as people can’t cry about the poor fish and all that.

“CANDU plants are designed to withstand standard earthquakes multiplied by a comfortable safety factor. They are, essentially pressurized heavy water reactors (PHWR’s) with vastly different heat sinks and cooling systems than available to BWRs (boiling water reactors) in Japan. A CANDU reactor has primary and secondary heat removal systems that do not connect but interface through steam generator tubes. One could start listing even more differences between a modern CANDU and Daiichi plant such as: the CANDU has two independent, horizontally oriented cooling loops composed of pressure tubes, not a pressure vessel; there are four standby generators for backup power, of which only one is required to supply power for long term core cooling. As a ‘backup to backup’ there are redundant, seismically qualified, emergency power generators out of which only one must operate to supply long term power needs. There are the post-accident hydrogen igniters that would burn any hydrogen before it reached explosive concentrations in the reactor vault. CANDU reactors have multiple safety systems addressing one type of accident and all critical equipment is environmentally qualified to perform its mission in a most adverse, post-accident environment.

CANDU reactors are designed to protect against or mitigate the effects of credible common mode failures such as a seismic event. A common mode failure, the tsunami initiated wetting of all emergency power supplies disabled emergency core cooling systems and caused multiple nuclear accidents at Fukushima.

High fields around reactors at Fukushima impeded access to their cooling ponds located in the reactor buildings. CANDU spent fuel bays are located outside of the reactor buildings.

CANDU nuclear power plants have huge spent fuel bays designed to hold all fuel removed from the reactor for ten years under a ten metre layer of water. Even with a prolonged interruption of bay water cooling and make-up, the water level would not be rapidly dropping due to evaporation as was the case at the Fukushima unit 4 cooling pond.

This is because of a difference in fuelling systems. In BWRs fuel from the entire core is replaced at once during fuelling outage (15 tons of spent fuel at one time). On the other hand, only a small quantity of spent fuel is removed from a CANDU reactor on a daily basis (about 0.27 % of the core inventory at a 935 MWe CANDU unit , approximately 320 kg or 16 fuel bundles). The difference in fuelling strategy in conjunction with the type of fuel used, results in the amount of residual heat being much lower in CANDU spent fuel bays than the amount of heat in the cooling ponds at Fukushima.

In terms of potential spread of radioactive contamination from damaged spent fuel, the cooling ponds at Fukushima are located at high elevation above ground. In contrast, CANDU reactors have their spent fuel stored under a 10 metre layer of water and the fuel resides below the ground level which impedes the spread of contamination to the environment.

Storing CANDU irradiated fuel in spent fuel bays is 100% safe and cannot cause out-of-core criticality. There is no physical possibility of CANDU spent fuel to ever go critical while submerged in demineralised water. CANDU fuel requires heavy water moderator in a special lattice to sustain a chain reaction.”

Hmm, well, even with a normal refuelling outage, about 1/3 of the fuel would be in the spent fuel pool.

Candu’s don’t have core shrouds, but they do have pressure tube replacement once every couple decades. But even then, the bigger spent fuel pool combined with below grade siting, and no possibility of recriticality in light water (need heavy water) gives it an inherent advantage during prolonged blackouts etc. Heck, you can walk up to it, plunk in a firehose and that’s it.

Did anybody see hungry beast on the ABC last night? On their ‘stuff said’ segment they quoted financialgreenwatch.org putting the cost to decommission fukushima at $90,000,000,000 and the cost to rebuild “fukushima power plant” – Dai-ichi I presume – at $600,000,000,000. I realise this segment is often used to quote silly very things people say, but it was presented in a very matter of fact manner, to a likely audience of anti’s. A quick browse through the FGW site showed it to be exactly what I expected. A quick google suggested the whole march earthquake rebuild cost could be up to $600b, so if that amount of money were just spent on reactors, I imagine Japan would put a pretty serious dent in their FF emissions.

I wonder if it’ll get a mention on mediawatch… I’d write to them, but I think I’d have more luck getting a church choir to belt out some tunes by slayer.

An official report, which Japan will submit to the UN’s nuclear watchdog, says nuclear fuel in three reactors at Fukushima has possibly melted through the pressure vessels and accumulated in outer containment vessels.

Japan’s Yomiuri Shimbun newspaper says this “melt-through” is far worse than a core meltdown, and is the worst possibility in a nuclear accident.

Poor, poor form HUNGRY BEAST!
RE: NinetySix – the worse thing is – you are incorrect as it was not on their ‘STUFF SAID’ segment which simply quotes random people, it was on their ‘factual and news’ segment called “FOLLOW THE MONEY” – which is presented as FACT and NEWS to viewers.
They stated as fact: “$600 billion to rebuild the Fukushima power plant”
Wrong! That is the estimated cost (up to) to rebuild the entire country from the earthquake and tsunami!

Further to MattB’s comment about the ABC report of a melt-through, today the reports are of PU and Sr 90 found in Fukushima township. Does anyone have any further information on this or is it just a journalist that’s gone off half cocked?

I understand that Sr 90 has a half life of 29 years so could it be from nuclear bombing 65 years ago?

There’s some fascinating discussion here – great thread. I’m a nuke with 13 years of experience (PWRs, so I’m not terribly familiar with BWR designs), and perhaps the major question for me is in regards to hydrogen control at the plant. In the advanced reactor design I was working on, passive hydrogen recombiners are used to avoid hydrogen buildup and explosions like those that occurred at Fukushima.

What hydrogen control mechanism was used at Fukushima, if anything? Did they have igniters that were lost with the LOOP? Is there no requirement in Japan for having hydrogen control devices?

There are quite a few things that really piss me off about this accident, including things that cannot be interpreted as anything but serious design flaws:

>> Putting emergency-critical electrical switch gear in a basement not hardened against floods is sheer stupidity. Anybody who has a basement knows they get flooded. Particularly if you live near water.

>> Putting in a SFP high in a building where it is coupled to the reactor in accidents is mind-boggling. If anything, locate it down low so it *does* get flooded.

>> Allowed hydrogen to vent into your reactor building rather than out a hardened stack or vent, and losing all hydrogen mitigation equipment concurrent with a LOOP.

>> Having no diversity in your emergency diesels (so that a single event takes out all 13) is anathema to what we are taught about reactor safety.

>> Not being able to simply airlift in batteries or diesels/diesel fuel and plug them in (to extend the coping period)

>> Siting a reactor on a beach in a tsunami prone area, then only planning for a 5 meter wave. Particularly when you have 500 year old tsunami stones on cliffs far above the beach:

I understand the catastrophic and extraordinarily rare initiating event for this accident, but it could have and should have been handled much better. It has done severe damage to our industry and our reputations.

TPL, they do have hydrogen recombiners, or there would be trouble in normal operation due to radiolysis gas buildup. But they are actively powered, need electricity for fans and such. That wasn’t there, so no or very little hydrogen recombination. I’m not sure if the active recombiners were spark igniters or fan powered flow over catalysts.

It’s sad, since passive hydrogen recombiners, that need no electricity, have been available on the market for some time now. And even the active igniters need very little electricity so can just have their own lithium batteries and keep working for months.

Definately agree that some funny stuff is going on here – in the negative sense. Putting the diesel generators high up, having redundant transformers and other electrical equipment in a seperate AC system, would have prevented the entire core damage sequence, and is so obvious it should have been detected by the regulators as a common mode failure risk. Venting hydrogen rich gas to the top of a building where the ventilation systems depend on external electricity supply, gee is that a good idea. Putting the spent fuel pool in that same explosion prone area a hundred feet up in the air, oh yes a very good design choice.

A simple firehose standpipe on all sides of the building with hardened spray nozzles above the spent fuel pool would have made refilling with water very easy.

Why was there no generator attached to the decay heat steam turbine cooling system? No power for the valves, not enough battery capacity. Amateur hour!

GE made serious and egregiously obvious design flaws in their oldest BWRs and the Japan regulators allowed it. I remain flabbergasted by this. Most of the technical improvements required cost very little.

I’m also disappointed in the political response to the events around the world. Germany’s response is absurd. They’re not going to close down their oil refineries despite serious problems with the oil refineries in Japan (burning for days, throwing out carginogenic half burned hydrocarbons).

People are talking about removing spent fuel from pools into dry casks, but that serves no point. Its the fresh fuel that’s the problem, and this cannot be put in dry casks yet. Plus only the high up fuel pools of older BWRs are vulnerable – at Daiichi there is also a central below grade storage pool and that’s fine. No chance of water sloshing or catastrophically breaking out, easy to refill and repair. Nothing wrong with below grade spent fuel pools. Add the hardened spray and standpipe connections is about the only technical measure one might improve on with these pools.

Its clear that nuclear power is entirely political and that most people don’t know a thing about the technology. Its not any different than thirty years ago. So sad.

An official report, which Japan will submit to the UN’s nuclear watchdog, says nuclear fuel in three reactors at Fukushima has possibly melted through the pressure vessels and accumulated in outer containment vessels.

The control rods on this type of reactor are inserted thru the bottom of the reactor. A high probability of leakage via the control rod seals has been assumed for some time.

BWR reactor designers have always argued that the many control rod housing tubes are a benefit in an accident because of the heat-bridge effect (enhanced cooling) that the extra surface area gives. It also makes it more likely that molten fuel will cool and solidify between the housing tubes. The part that does not will drop onto the containment floor. In unit 1 at least that part of the containment has been flooded with water. So that’s effectively cooled. Flooding that lower part of the drywell (containment) is used in most BWRs as in-vessel melt retention & arrest. This is better than letting the molten fuel escape the vessel because it doesn’t challenge the concrete containment below. Should any chunks of fuel penetrate the vessel anyway, they are effectively cooled by dropping into the deluge water there.

I still don’t get that they didn’t filter the steam overpressure relief operations early in the accident. They’ve got filters for the seawater injection boil off steam, removing the radioactive particles before the steam is released through a big vent in the building wall. There’s just way too much iodine released for it to be a filtered vent path.

Despite the dramatic headline, if you read through to the end of the article you find nuclear scientist Yoshiaki Oka is quoted “… we now know that this happened at the very beginning of the accident, so I see no particular additional affects on human health”.

Does anyone know the basis of the “$250 billion” cost estimate claim in the article? (i.e. which “studies”?)

Does anyone know the basis of the “$250 billion” cost estimate claim in the article?

Some University professer.

The costs broke out as $8 billion for short term compensation(IMHO an accurate estimate).

$54 billion to buy all the real estate within a 20 km radius. The radiation levels within a 20km radius vary by a factor of 100..so how much will be declared safe, how much will be mitigated and how much will have to end up being a long term exclusion zone is at this point unknown.

I can’t imagine that it would be cheaper to buy someones house then send out a backhoe and dump truck and scrape up the top 6″ of top soil and cart it off and replace it with fresh top soil. On the other hand it would probably be cheaper to buy a forest then attempt to mitigate but then I don’t know if Japan has a radiation safety standard for forest products.

Then the remainder was a WAG as to decommissioning costs…between $9 billion and $188 billion.

Well worth the read to see how they came up with the $90b figure… I guess if you wish for something hard enough, it just might come true.

That telegraph article reminds me of several media outlets interpretation of the WHO’s recent bit about mobile phones and brain tumors … insisting your children will die while quietly mentioning that the data is highly unscientific and no conclusions can yet be drawn. So nothing has changed, worry if you want to etc, etc…

NinetySix, on 10 June 2011 at 9:27 AM — I think that estimate is complete nonsense. First of all, only three units have suffered actual recator damage, roughly comperable to Three Mile Island (TMI). Decommsioning that unit cast almost a US$ one billion. Factoring in inflation and addional difficultiers, say US$ 4 billion for each of the four damaged units. That’s US$ 16 billion plus the normal decommising costs for the relatviely undamged readots.

Eric Moore, I believe the steam eminating from the higher portion of the building is from the boil off from the freshwater injection cooling. The water is boiled off from the decay heat, turns into steam that passes through the reactor vessel through a filter system that removes radionuclides, and then vents the cleaned up steam up into the air through a large vent in the side of the building.

There are confusing reports as to how this is done specifically. But the water they inject through the fire extinguishing line has to be vented – which is why they must inject fresh water constantly. I think this also causes recirculated waste streams (condensate, brine etc.) which contributes to the large volumes of radioactive water at the plant that must be cleaned up through the water treatment plant TEPCO is setting up right now. If they clean the water of both radionuclides and salt they can re-inject the cleaned water back into the coolant injection line for more cooling. This would minimise the amount of low radioactive water and would leave a much smaller volume of radioactive brines eventually. I think this final brine gunk can be boiled leaving a concentrate dry waste product in the filters and concentrate residues, that can be stored in dry casks (as one would store spent fuel normally) or in medium level waste storage facilities.

I see the media is reporting high levels of strontium in ground water and seawater around Fukushima, is this likely to be coming from the cooling water, or is it an indication of deeper problems?
Does this find give more ammunition to the anti-nuclear argument?MODERATOR
Please supply the links/refs to the articles as per BNC Comments Policy. Please read the Citation Policy on the About page. We need more in-put from you demonstarting you have read and understood the literature.

there are also radioactive readings above the limit in a town call Date:

“Date is about 60 kilometers from the troubled Fukushima Daiichi nuclear plant. The central government announced earlier this month that the accumulated radiation levels at 3 locations in the city’s Ryozen area are estimated to exceed 20 millisieverts for the year that ends next March. People living in areas receiving this amount of radiation are urged to evacuate within a month.”

Strontium is found everywhere on earth due to atmospheric bomb testing decades ago. You can find a map of it here:

As you can see Japan is a hot spot for weapons testing derived strontium-90.

Definitive proof of strontium emission of Fukushima is not there, at all.

Such proof would be there if they find significant amounts of strontium-89. This isotope is much shorter lived and the weapons testing decades ago would have allowed almost all of it to decay. If they find any, it will be from Fukushima.

Sr-89 has not been detected by TEPCO, to my knowledge.

Almost all of the exposure around Fukushima comes from cesium-137 and 134 that are powerful gamma emitters.

Evacuating over 20 mSv/year external gamma dose (Cs-137 and 134) is nonsense. Such dose appears to have strong beneficial effects on health (up to 525 mSv/year is beneficial) according to the Taiwanese cobalt-60 accident. (cobalt-60 is a strong gamma emitter, more powerful than cesium-137 due to its shorter half life)

“TEPCO also said that strontinum-90 was detected at a level 170 times higher than the standard in samples also taken on May 16, near the water intakes outside reactor number 2. At the reactor number 3 water intakes, the level was 240 times higher than the legal safety limit.”

the idea that we have Strontium at 240 times the legal limit because of nuclear tests 50 years ago is utterly absurd. but perhaps you have a link that suggests that such levels of strontium are common?!?

@ Sod. Water intakes, yes because strontium forms water soluble species that go into the emergency coolant/leaked water on site. This isn’t what we are worried about here – we want to know about strontium fallout that was volatilized and thus spread out over a large land area. This is what happened to cesium because it is volatile so it comes with the vented containment pressure relief operations. Strontium isn’t very volatile at all, so land based fallout for strontium can be expected to be low.

There seems to be no mention of Sr-89, which is odd. Far more radioactive and easier to detect, and if found in land samples it would suggest clearly that the strontium was volatilized and comes from Fukushima.

The land based samples of Sr-90 are so low it is no threat and likely all/most due to the atmospheric bomb testing. Which is perfectly as expected.

Strontium has very roughly similar low volatility as plutonium. Also looking at Chernobyl gives a reference to how much of the nuclides are released (strontium roughly similar to plutonium).

If you’re not finding lots of plutonium from fallout, you won’t find lots of strontium from fallout. But there is lots of plutonium and strontium in the contaminated water, which TEPCO must now filter out.

What I am not hearing (perhaps because they don’t know) is what was really the “straw that broke the camel’s back” in terms of containment integrity. Was it the massive hydrogen explosions, or was it the high-G earthquake. It is odd to me that everyone focuses on the flooding (the initiating event), but not the hydrogen explosions or the earthquake. For everything that went wrong, the integrity of the containment is ultimately what must be protected.

Any speculation/information on why this failed. Did excessive pressure due to lack of venting pop the containment, or was it already opened up due to the earthquake? Or was it a combination of these factors plus the explosions?

Also, I’m having a lot of trouble finding information on exactly where the containment is breached in the three units. Are there data for the breach locations, size, etc?

Why did the containments fail, well it seems obvious that they would after taking that level of punishment. There are many challenges to the containment and its a wonder the things held up the way they did. Let’s break it down (pardon the pun).

First there’s an earthquake with 4 or 5 times the design ground accelleration.

Second there’s a huge wave of water putting forces on the building, with unknown damage effect to the containment (though fairly well known effect on site electrical infrastrure).

Third the crazy operators allow 2x design pressure (850 kPag) and at least 150 degrees Celcius higher temperature than design to build up in the containment, before they decided to vent to atmosphere. This must have ruined various pump and equipment seals as well as further stressing an already challenged containment.

Fourth the design flaw of venting potentially hydrogen rich gas and high activity material into the top section of the building, causing massive explosions that further shook the containments.

Much of the containment problems above can be solved by having a passive automatic containment venting system that vents up a tall chimney. I’m thinking about a U-shaped pipe where the bottom is filled with water, connecting to the containment in one leg and to the outside stack on the other. Pressure rising means the water gets pushed down, up to the point that it reaches the bottom of the U-pipe, and then the excess pressure will bubble out through the stack, also scrubbing it of cesium and other radionuclides. There should be extra carbon filters on both ends of the pipe just in case.

More regarding the containment, the World Nuclear article suggests that most radioactivity was released by the rupture of the containment of unit 2 after the hydrogen explosion. That points to the hydrogen explosion as the culprit.

“At Daiichi there is still no data for units 1, 2 and 5, but available figures put the maximum acceleration as 507 gal from east to west at unit 3. The design basis for this was 441 gal. Other readings were below design basis, although east-west readings at unit 6 of 431 gal approached the design basis of 448 gal.”

Again, I realize this thread is for assertions of belief and opinion and you aren’t required by the rules to give a reason for the numbers you’re posting.

It would be a kindness for those who want actual facts, if you’d do so.

Figures Released On Fukushima-Daiichi Seismic Design Reference Values
Sunday, 20 March 2011
The maximum ground acceleration near unit 3 of the Fukushima-Daiichi nuclear plant from the earthquake that struck northern Japan on 11 March 2011 was 507 gal – or 507 centimetres per second squared – which is above the plant’s design reference values of 449 gal, the Japan Atomic Industrial Forum (JAIF) said today.http://www.sone.org.uk/content/view/1920/2/

Correct Hank, the acceleration was only a small percentage above the limits. It was the total earthquake energy that was so much higher than expected, but of course that is not what is actually experienced at any one nuclear plant. My vague recollection is that the shaking went on for a very long time (reflecting the high energy). I don’t know if there is a time-based limit on how long the nuclear plant is designed to endure its maximum shaking; if not, perhaps there should be.

The World Nuclear website says the plants were upgraded in the 80s and 90s for higher earthquake protection. Too bad they didn’t increase the tsunami protection, despite the fact that a higher tsunami was predicted, according to the World Nuclear website.

Are the gal numbers for the lateral movement only, or are they also for axial movement? Some kind of normalized number?

For reference, here is the World Nuclear link, updated recently, a very nice summary with lots of numbers:

“in Kobe, the shake of 800gal or more is recorded. The 818gal in the directions of north and south, the 617gal in the directions of east and west, and the 332gal in the vertical directions are recorded at the Kobe Marine Observatories at the Hyogo southern part earthquake in 1995. (Fig. 16)”

“PGA or Design Basis Earthquake Ground Motion is measured in Galileo units – Gal (cm/sec2) or g – the force of gravity, one g being 980 Gal. …
…
PGA has long been considered an unsatisfactory indicator of damage to structures, and some seismologists are proposing to replace it with Cumulative Average Velocity (CAV) as a more useful measure since it brings in displacement and duration.”

More and different measurements beyond the one World-Nuclear mentions turn up with searching:

“… The SAFER Project initiated the parameter optimization in the Istanbul Earthquake Early Warning System IEEWS (Fig. 24). The existing IEEWS utilizes band-pass filtered PGA and CAV values. A new parameter called Bracketed Cumulative Average Velocity (BCAV) has been proposed to be used in the IEEWS. As a new approach the specific window-based BCAV namely BCAV-W is planned to be used in IEEWS….”http://www.saferproject.net/doc/dissemination/SAFER_Final_Report.pdf

“SAFER (Seismic Early Warning for Europe) is a project funded by the European Commission in the context of Framework Program 6 under the Theme Sustainable Development, Global Change and Ecosystems.”

@Cyril R “… the crazy operators allow 2x design pressure … and at least 150 degrees .. higher … than design to build up in the containment, before they decided to vent to atmosphere. This must have ruined …. ”

It sure is crazy from a technical point of view. And the health fears were probably crazy from a radiation health expert’s point of view. However the environment of those decision-makers was not technical, so much as political, under a terrific pressure from a minefield of vindictive regulations.

There is currently underway a stress testing process across Europe’s reactors. Let us hope that it exposes the craziness of the restrictions imposed. Perhaps proportionate measures will be put in place for timely assessment of any health threats to the neighbourhood. Timely enough for operators to make rational decisions in crises.

Roger, yes, the fact that politicians can decide when to vent an overpressurized containment, is scary. That’s why I want this system to be fully passive. One way to do it is to put a U-shaped pipe in the containment, with one end sticking out to the outside air, the other connected to containment, and isolation achieved through water in the bottom of the U section. If the pressure rises, the water will be pushed down in the containment side of the pipe, until it reaches the bottom of the U pipe, causing it to vent out through the pushed up water column on in the other side of the pipe. This scrubs the fission products as well. These type of functions are so vital they should be fully passive and automatic. Operators shouldn’t be able to override them. Put extra carbon and particulate filters in the pipe just in case iodine and cesium make it through.

The European stress test looks good. They’re going to look at some really extreme events, such as a blackout combined with a 9/11 style aircraft crash attack. But I hope they will allow changes to be made to existing plants to make them resistant against all that, if it proves necessary. I hope no more plants are shut down.

“I’m about to discuss a medical organization that is steeped in an utterly toxic brew of bad science and extreme ideology. So what? you might ask…. when it comes to medical science, this organization deserves every harsh word that I am about to write because it is a major booster of antivaccinationism, HIV/AIDS denialism, and the now discredited hypothesis that abortion causes breast cancer, while on its pages it regularly attacks the very concept of evidence-based medicine and peer-review. That it is an organization of physicians is all the more appalling….”

@Martin Nicholson : They are a number of serious papers supporting radiation hormesis but this one is not one of them. A constant irradiation level near the 10 Gy/y range is extremely harmful and will cause fatal leukemia in most case, as is amply demonstrated by the unfortunate Kramatorsk nuclear poisoning incident :http://en.wikipedia.org/wiki/Kramatorsk_nuclear_poisoning_incident

Give me some clue how you want that cited, or if it’s inadmissable to mention that this has already been beaten to death here in prior topics, just say you won’t allow it to be disputed again.MODERATOR
You can state that it has been comprehensively dealt with on BNC and suggest that people do the research before commenting. It is OK to link to BNC pages after saying that. For the record it was probably a mistake of mine to delete these two instances – however they followed on the heels of two other non BNC links which were light on comment before posting the link, so they were dealt with in the same way. You have been inserting a lot of quick remarks with links and these have been let stand but it is important that regular contributors abide by the citation policy as well as newcomers.

@jmdesp Luckey suggests that 1 Gy/y is acceptable and 0.1 Gy/y is optimal. I don’t think he is advocating 10 Gy/y. Why do you consider that Luckey’s article is not a serious paper?

I have no view one way or the other about Luckey’s veracity but I notice that the material referred to by Cyril R has several references to Luckey’s work so presumable the authors published in BELLE take him seriously.

I asked earlier if anyone knew how prepared the accident site was to deal with a major typhoon? The question is now more than hypothetical with the predicted path of Typhoon Ma-On indicating a possible direct hit on the Fukushima Region:

Nuclear power is must for survival of the earth but it has to be safe also. Unfortunatily most of the persons in the nuclear industry feel that each plant design is safe. it is evident from the statements of heads of most of the NPPs just after the Fukushima accident. Every ECO was saying that their plants are safe and a Fukushima like incident can not happen in their plant even without knowing that what has actually happened in Fukushima. since at time very little and confusing information was available. It is surpising that how one can claim that a particular type of incident will not take place in his plant even without knowing the incident itself. it decreases creadibility and people start suspecting these statements and rightly so. I can say that many of the plants design is not safe but they have got licence to operate. Most the the safety reviews are just showpiece and they are meant to fool the public. I do not say that all the designs are unsafe and some are definitely not safe. It is important to accept the flaws and plug it but people in the industry are not ready to accept flaws. they have perceptional blindness and not able to see the other side (unfsafe side) of the coin. It is important that public put pressure on plant managements to be transparent and prove that their design safe. it is a fact that transparency is lagging in this industry and everyone tries to hide the facts not only from public but even among themselves.
For survival of nuclear power safe design is a must which is not right now.
Thank you,
John.